[PATCH v4 0/2] Touch Bar DRM driver for x86 Macs

[PATCH v4 0/2] Touch Bar DRM driver for x86 Macs

[Aditya Garg]

The following patch series aims to add support for the DRM mode of the
Touch Bar found on x86 Macs. The DRM mode enables the Touch Bar to act
as a second display, just like macOS.

The first patch adds emulation helper from XRGB8888 to BGR888 which is
needed by this device and the driver.

The second patch is the main DRM driver, required for the DRM mode.
Currently, only T2 Macs are supported.

Currently, a daemon named tiny-dfr [1] by Asahi Linux supports the
Touch Bar in this mode by displaying the Function and Media keys.
More such daemons can be made with more customisation in the future.

[1]: https://github.com/AsahiLinux/tiny-dfr

Kerem Karabay (2):
  drm/format-helper: Add conversion c
  drm/tiny: add driver for Apple Touch Bars in x86 Macs

 MAINTAINERS                                   |   8 +
 drivers/gpu/drm/drm_format_helper.c           |  54 ++
 .../gpu/drm/tests/drm_format_helper_test.c    |  81 ++
 drivers/gpu/drm/tiny/Kconfig                  |  14 +
 drivers/gpu/drm/tiny/Makefile                 |   1 +
 drivers/gpu/drm/tiny/appletbdrm.c             | 835 ++++++++++++++++++
 include/drm/drm_format_helper.h               |   3 +
 7 files changed, 996 insertions(+)
 create mode 100644 drivers/gpu/drm/tiny/appletbdrm.c

-- 
2.43.0

[PATCH v4 1/2] drm/format-helper: Add conversion from XRGB8888 to BGR888

[Aditya Garg]

From: Kerem Karabay <kekrby@gmail.com>

Add XRGB8888 emulation helper for devices that only support BGR888.

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
---
v2 -> Fix incorrect description
v3 -> No change in this patch
v4 -> No change in this patch

 drivers/gpu/drm/drm_format_helper.c           | 54 +++++++++++++
 .../gpu/drm/tests/drm_format_helper_test.c    | 81 +++++++++++++++++++
 include/drm/drm_format_helper.h               |  3 +
 3 files changed, 138 insertions(+)

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index b1be458ed..4f60c8d8f 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -702,6 +702,57 @@ void drm_fb_xrgb8888_to_rgb888(struct iosys_map *dst, const unsigned int *dst_pi
 }
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb888);
 
+static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
+{
+	u8 *dbuf8 = dbuf;
+	const __le32 *sbuf32 = sbuf;
+	unsigned int x;
+	u32 pix;
+
+	for (x = 0; x < pixels; x++) {
+		pix = le32_to_cpu(sbuf32[x]);
+		/* write red-green-blue to output in little endianness */
+		*dbuf8++ = (pix & 0x00ff0000) >> 16;
+		*dbuf8++ = (pix & 0x0000ff00) >> 8;
+		*dbuf8++ = (pix & 0x000000ff) >> 0;
+	}
+}
+
+/**
+ * drm_fb_xrgb8888_to_bgr888 - Convert XRGB8888 to BGR888 clip buffer
+ * @dst: Array of BGR888 destination buffers
+ * @dst_pitch: Array of numbers of bytes between the start of two consecutive scanlines
+ *             within @dst; can be NULL if scanlines are stored next to each other.
+ * @src: Array of XRGB8888 source buffers
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ * @state: Transform and conversion state
+ *
+ * This function copies parts of a framebuffer to display memory and converts the
+ * color format during the process. Destination and framebuffer formats must match. The
+ * parameters @dst, @dst_pitch and @src refer to arrays. Each array must have at
+ * least as many entries as there are planes in @fb's format. Each entry stores the
+ * value for the format's respective color plane at the same index.
+ *
+ * This function does not apply clipping on @dst (i.e. the destination is at the
+ * top-left corner).
+ *
+ * Drivers can use this function for BGR888 devices that don't natively
+ * support XRGB8888.
+ */
+void drm_fb_xrgb8888_to_bgr888(struct iosys_map *dst, const unsigned int *dst_pitch,
+			       const struct iosys_map *src, const struct drm_framebuffer *fb,
+			       const struct drm_rect *clip, struct drm_format_conv_state *state)
+{
+	static const u8 dst_pixsize[DRM_FORMAT_MAX_PLANES] = {
+		3,
+	};
+
+	drm_fb_xfrm(dst, dst_pitch, dst_pixsize, src, fb, clip, false, state,
+		    drm_fb_xrgb8888_to_bgr888_line);
+}
+EXPORT_SYMBOL(drm_fb_xrgb8888_to_bgr888);
+
 static void drm_fb_xrgb8888_to_argb8888_line(void *dbuf, const void *sbuf, unsigned int pixels)
 {
 	__le32 *dbuf32 = dbuf;
@@ -1035,6 +1086,9 @@ int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t d
 		} else if (dst_format == DRM_FORMAT_RGB888) {
 			drm_fb_xrgb8888_to_rgb888(dst, dst_pitch, src, fb, clip, state);
 			return 0;
+		} else if (dst_format == DRM_FORMAT_BGR888) {
+			drm_fb_xrgb8888_to_bgr888(dst, dst_pitch, src, fb, clip, state);
+			return 0;
 		} else if (dst_format == DRM_FORMAT_ARGB8888) {
 			drm_fb_xrgb8888_to_argb8888(dst, dst_pitch, src, fb, clip, state);
 			return 0;
diff --git a/drivers/gpu/drm/tests/drm_format_helper_test.c b/drivers/gpu/drm/tests/drm_format_helper_test.c
index 08992636e..35cd3405d 100644
--- a/drivers/gpu/drm/tests/drm_format_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_format_helper_test.c
@@ -60,6 +60,11 @@ struct convert_to_rgb888_result {
 	const u8 expected[TEST_BUF_SIZE];
 };
 
+struct convert_to_bgr888_result {
+	unsigned int dst_pitch;
+	const u8 expected[TEST_BUF_SIZE];
+};
+
 struct convert_to_argb8888_result {
 	unsigned int dst_pitch;
 	const u32 expected[TEST_BUF_SIZE];
@@ -107,6 +112,7 @@ struct convert_xrgb8888_case {
 	struct convert_to_argb1555_result argb1555_result;
 	struct convert_to_rgba5551_result rgba5551_result;
 	struct convert_to_rgb888_result rgb888_result;
+	struct convert_to_bgr888_result bgr888_result;
 	struct convert_to_argb8888_result argb8888_result;
 	struct convert_to_xrgb2101010_result xrgb2101010_result;
 	struct convert_to_argb2101010_result argb2101010_result;
@@ -151,6 +157,10 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 			.dst_pitch = TEST_USE_DEFAULT_PITCH,
 			.expected = { 0x00, 0x00, 0xFF },
 		},
+		.bgr888_result = {
+			.dst_pitch = TEST_USE_DEFAULT_PITCH,
+			.expected = { 0xFF, 0x00, 0x00 },
+		},
 		.argb8888_result = {
 			.dst_pitch = TEST_USE_DEFAULT_PITCH,
 			.expected = { 0xFFFF0000 },
@@ -217,6 +227,10 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 			.dst_pitch = TEST_USE_DEFAULT_PITCH,
 			.expected = { 0x00, 0x00, 0xFF },
 		},
+		.bgr888_result = {
+			.dst_pitch = TEST_USE_DEFAULT_PITCH,
+			.expected = { 0xFF, 0x00, 0x00 },
+		},
 		.argb8888_result = {
 			.dst_pitch = TEST_USE_DEFAULT_PITCH,
 			.expected = { 0xFFFF0000 },
@@ -330,6 +344,15 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 				0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x00,
 			},
 		},
+		.bgr888_result = {
+			.dst_pitch = TEST_USE_DEFAULT_PITCH,
+			.expected = {
+				0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00,
+				0xFF, 0x00, 0x00, 0x00, 0xFF, 0x00,
+				0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF,
+				0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF,
+			},
+		},
 		.argb8888_result = {
 			.dst_pitch = TEST_USE_DEFAULT_PITCH,
 			.expected = {
@@ -468,6 +491,17 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 				0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 			},
 		},
+		.bgr888_result = {
+			.dst_pitch = 15,
+			.expected = {
+				0x0E, 0x44, 0x9C, 0x11, 0x4D, 0x05, 0xA8, 0xF3, 0x03,
+				0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				0x6C, 0xF0, 0x73, 0x0E, 0x44, 0x9C, 0x11, 0x4D, 0x05,
+				0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+				0xA8, 0x03, 0x03, 0x6C, 0xF0, 0x73, 0x0E, 0x44, 0x9C,
+				0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			},
+		},
 		.argb8888_result = {
 			.dst_pitch = 20,
 			.expected = {
@@ -914,6 +948,52 @@ static void drm_test_fb_xrgb8888_to_rgb888(struct kunit *test)
 	KUNIT_EXPECT_MEMEQ(test, buf, result->expected, dst_size);
 }
 
+static void drm_test_fb_xrgb8888_to_bgr888(struct kunit *test)
+{
+	const struct convert_xrgb8888_case *params = test->param_value;
+	const struct convert_to_bgr888_result *result = &params->bgr888_result;
+	size_t dst_size;
+	u8 *buf = NULL;
+	__le32 *xrgb8888 = NULL;
+	struct iosys_map dst, src;
+
+	struct drm_framebuffer fb = {
+		.format = drm_format_info(DRM_FORMAT_XRGB8888),
+		.pitches = { params->pitch, 0, 0 },
+	};
+
+	dst_size = conversion_buf_size(DRM_FORMAT_BGR888, result->dst_pitch,
+				       &params->clip, 0);
+	KUNIT_ASSERT_GT(test, dst_size, 0);
+
+	buf = kunit_kzalloc(test, dst_size, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);
+	iosys_map_set_vaddr(&dst, buf);
+
+	xrgb8888 = cpubuf_to_le32(test, params->xrgb8888, TEST_BUF_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, xrgb8888);
+	iosys_map_set_vaddr(&src, xrgb8888);
+
+	/*
+	 * BGR888 expected results are already in little-endian
+	 * order, so there's no need to convert the test output.
+	 */
+	drm_fb_xrgb8888_to_bgr888(&dst, &result->dst_pitch, &src, &fb, &params->clip,
+				  &fmtcnv_state);
+	KUNIT_EXPECT_MEMEQ(test, buf, result->expected, dst_size);
+
+	buf = dst.vaddr; /* restore original value of buf */
+	memset(buf, 0, dst_size);
+
+	int blit_result = 0;
+
+	blit_result = drm_fb_blit(&dst, &result->dst_pitch, DRM_FORMAT_BGR888, &src, &fb, &params->clip,
+				  &fmtcnv_state);
+
+	KUNIT_EXPECT_FALSE(test, blit_result);
+	KUNIT_EXPECT_MEMEQ(test, buf, result->expected, dst_size);
+}
+
 static void drm_test_fb_xrgb8888_to_argb8888(struct kunit *test)
 {
 	const struct convert_xrgb8888_case *params = test->param_value;
@@ -1851,6 +1931,7 @@ static struct kunit_case drm_format_helper_test_cases[] = {
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_argb1555, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_rgba5551, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_rgb888, convert_xrgb8888_gen_params),
+	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_bgr888, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_argb8888, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_xrgb2101010, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_argb2101010, convert_xrgb8888_gen_params),
diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h
index 428d81afe..aa1604d92 100644
--- a/include/drm/drm_format_helper.h
+++ b/include/drm/drm_format_helper.h
@@ -96,6 +96,9 @@ void drm_fb_xrgb8888_to_rgba5551(struct iosys_map *dst, const unsigned int *dst_
 void drm_fb_xrgb8888_to_rgb888(struct iosys_map *dst, const unsigned int *dst_pitch,
 			       const struct iosys_map *src, const struct drm_framebuffer *fb,
 			       const struct drm_rect *clip, struct drm_format_conv_state *state);
+void drm_fb_xrgb8888_to_bgr888(struct iosys_map *dst, const unsigned int *dst_pitch,
+			       const struct iosys_map *src, const struct drm_framebuffer *fb,
+			       const struct drm_rect *clip, struct drm_format_conv_state *state);
 void drm_fb_xrgb8888_to_argb8888(struct iosys_map *dst, const unsigned int *dst_pitch,
 				 const struct iosys_map *src, const struct drm_framebuffer *fb,
 				 const struct drm_rect *clip, struct drm_format_conv_state *state);
-- 
2.43.0

Re: [PATCH v4 1/2] drm/format-helper: Add conversion from XRGB8888 to BGR888

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 01:38:32PM +0000, Aditya Garg wrote:
> From: Kerem Karabay <kekrby@gmail.com>
> 
> Add XRGB8888 emulation helper for devices that only support BGR888.

...

> +static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)

Okay the xrgb8888 is the actual pixel format independently on
the CPU endianess.

> +{
> +	u8 *dbuf8 = dbuf;
> +	const __le32 *sbuf32 = sbuf;

But here we assume that sbuf is __le32.
And I think we may benefit from the __be32 there.

> +	unsigned int x;
> +	u32 pix;
> +
> +	for (x = 0; x < pixels; x++) {
> +		pix = le32_to_cpu(sbuf32[x]);
> +		/* write red-green-blue to output in little endianness */
> +		*dbuf8++ = (pix & 0x00ff0000) >> 16;
> +		*dbuf8++ = (pix & 0x0000ff00) >> 8;
> +		*dbuf8++ = (pix & 0x000000ff) >> 0;

		pix = be32_to_cpu(sbuf[4 * x]) >> 8;
		put_unaligned_le24(pix, &dbuf[3 * x]);

> +	}

Or, after all, this __le32 magic might be not needed at all. Wouldn't the below
be the equivalent

static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
{
	unsigned int x;
	u32 pix;

	for (x = 0; x < pixels; x++) {
		/* Read red-green-blue from input in big endianess and... */
		pix = get_unaligned_be24(sbuf + x * 4 + 1);
		/* ...write it to output in little endianness. */
		put_unaligned_le24(pix, dbuf + x * 3);
	}
}

The comments can even be dropped as the code quite clear about what's going on.

> +}

But it's up to you. I don't know which solution gives better code generation
either.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 1/2] drm/format-helper: Add conversion from XRGB8888 to BGR888

[Aditya Garg]

This conversion helper mimics the existing drm_fb_xrgb8888_to_rgb888 helper

> On 24 Feb 2025, at 7:59 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 01:38:32PM +0000, Aditya Garg wrote:
>> From: Kerem Karabay <kekrby@gmail.com>
>> 
>> Add XRGB8888 emulation helper for devices that only support BGR888.
> 
> ...
> 
>> +static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> 
> Okay the xrgb8888 is the actual pixel format independently on
> the CPU endianess.
> 
>> +{
>> + u8 *dbuf8 = dbuf;
>> + const __le32 *sbuf32 = sbuf;
> 
> But here we assume that sbuf is __le32.
> And I think we may benefit from the __be32 there.

So, like drm_fb_xrgb8888_to_rgb888, we are using __le32

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n657


> 
>> + unsigned int x;
>> + u32 pix;
>> +
>> + for (x = 0; x < pixels; x++) {
>> + pix = le32_to_cpu(sbuf32[x]);
>> + /* write red-green-blue to output in little endianness */
>> + *dbuf8++ = (pix & 0x00ff0000) >> 16;
>> + *dbuf8++ = (pix & 0x0000ff00) >> 8;
>> + *dbuf8++ = (pix & 0x000000ff) >> 0;
> 
> pix = be32_to_cpu(sbuf[4 * x]) >> 8;
> put_unaligned_le24(pix, &dbuf[3 * x]);

Again, 

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n664
> 
>> + }
> 
> Or, after all, this __le32 magic might be not needed at all. Wouldn't the below
> be the equivalent
> 
> static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> {
> unsigned int x;
> u32 pix;
> 
> for (x = 0; x < pixels; x++) {
> /* Read red-green-blue from input in big endianess and... */
> pix = get_unaligned_be24(sbuf + x * 4 + 1);
> /* ...write it to output in little endianness. */
> put_unaligned_le24(pix, dbuf + x * 3);
> }
> }
> 
> The comments can even be dropped as the code quite clear about what's going on.

These comments are literally rewritten :

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n663

> 
>> +}
> 
> But it's up to you. I don't know which solution gives better code generation
> either.

I don't really mind any code change tbh, but I’d prefer that as an improvement to existing code, and not a part of this patchset.

Re: [PATCH v4 1/2] drm/format-helper: Add conversion from XRGB8888 to BGR888

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 02:54:07PM +0000, Aditya Garg wrote:
> This conversion helper mimics the existing drm_fb_xrgb8888_to_rgb888 helper

Not really. See below.

> > On 24 Feb 2025, at 7:59 PM, andriy.shevchenko@linux.intel.com wrote:
> > On Mon, Feb 24, 2025 at 01:38:32PM +0000, Aditya Garg wrote:

...

> >> +static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> > 
> > Okay the xrgb8888 is the actual pixel format independently on
> > the CPU endianess.
> > 
> >> +{
> >> + u8 *dbuf8 = dbuf;
> >> + const __le32 *sbuf32 = sbuf;
> > 
> > But here we assume that sbuf is __le32.
> > And I think we may benefit from the __be32 there.
> 
> So, like drm_fb_xrgb8888_to_rgb888, we are using __le32
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n657

The rgb888 != bgr888, that's where the byte swapping happens. So, one should
use __be32 if the other has already been using __le32.

> >> + unsigned int x;
> >> + u32 pix;
> >> +
> >> + for (x = 0; x < pixels; x++) {
> >> + pix = le32_to_cpu(sbuf32[x]);
> >> + /* write red-green-blue to output in little endianness */
> >> + *dbuf8++ = (pix & 0x00ff0000) >> 16;
> >> + *dbuf8++ = (pix & 0x0000ff00) >> 8;
> >> + *dbuf8++ = (pix & 0x000000ff) >> 0;
> > 
> > pix = be32_to_cpu(sbuf[4 * x]) >> 8;
> > put_unaligned_le24(pix, &dbuf[3 * x]);
> 
> Again, 
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n664

As per above.

> >> + }
> > 
> > Or, after all, this __le32 magic might be not needed at all. Wouldn't the below
> > be the equivalent
> > 
> > static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> > {
> > unsigned int x;
> > u32 pix;
> > 
> > for (x = 0; x < pixels; x++) {
> > /* Read red-green-blue from input in big endianess and... */
> > pix = get_unaligned_be24(sbuf + x * 4 + 1);
> > /* ...write it to output in little endianness. */
> > put_unaligned_le24(pix, dbuf + x * 3);
> > }
> > }
> > 
> > The comments can even be dropped as the code quite clear about what's going on.
> 
> These comments are literally rewritten :
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n663
> 
> >> +}
> > 
> > But it's up to you. I don't know which solution gives better code generation
> > either.
> 
> I don't really mind any code change tbh, but I’d prefer that as an
> improvement to existing code, and not a part of this patchset.

Right, but see my argumentation above.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 1/2] drm/format-helper: Add conversion from XRGB8888 to BGR888

[Aditya Garg]

> On 24 Feb 2025, at 8:30 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 02:54:07PM +0000, Aditya Garg wrote:
>> This conversion helper mimics the existing drm_fb_xrgb8888_to_rgb888 helper
> 
> Not really. See below.
> 
>>> On 24 Feb 2025, at 7:59 PM, andriy.shevchenko@linux.intel.com wrote:
>>> On Mon, Feb 24, 2025 at 01:38:32PM +0000, Aditya Garg wrote:
> 
> ...
> 
>>>> +static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
>>> 
>>> Okay the xrgb8888 is the actual pixel format independently on
>>> the CPU endianess.
>>> 
>>>> +{
>>>> + u8 *dbuf8 = dbuf;
>>>> + const __le32 *sbuf32 = sbuf;
>>> 
>>> But here we assume that sbuf is __le32.
>>> And I think we may benefit from the __be32 there.
>> 
>> So, like drm_fb_xrgb8888_to_rgb888, we are using __le32
>> 
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n657
> 
> The rgb888 != bgr888, that's where the byte swapping happens. So, one should
> use __be32 if the other has already been using __le32.
> 
>>>> + unsigned int x;
>>>> + u32 pix;
>>>> +
>>>> + for (x = 0; x < pixels; x++) {
>>>> + pix = le32_to_cpu(sbuf32[x]);
>>>> + /* write red-green-blue to output in little endianness */
>>>> + *dbuf8++ = (pix & 0x00ff0000) >> 16;
>>>> + *dbuf8++ = (pix & 0x0000ff00) >> 8;
>>>> + *dbuf8++ = (pix & 0x000000ff) >> 0;
>>> 
>>> pix = be32_to_cpu(sbuf[4 * x]) >> 8;
>>> put_unaligned_le24(pix, &dbuf[3 * x]);
>> 
>> Again, 
>> 
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n664
> 
> As per above.
> 
>>>> + }
>>> 
>>> Or, after all, this __le32 magic might be not needed at all. Wouldn't the below
>>> be the equivalent
>>> 
>>> static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
>>> {
>>> unsigned int x;
>>> u32 pix;
>>> 
>>> for (x = 0; x < pixels; x++) {
>>> /* Read red-green-blue from input in big endianess and... */
>>> pix = get_unaligned_be24(sbuf + x * 4 + 1);
>>> /* ...write it to output in little endianness. */
>>> put_unaligned_le24(pix, dbuf + x * 3);
>>> }
>>> }
>>> 
>>> The comments can even be dropped as the code quite clear about what's going on.
>> 
>> These comments are literally rewritten :
>> 
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n663
>> 
>>>> +}
>>> 
>>> But it's up to you. I don't know which solution gives better code generation
>>> either.
>> 
>> I don't really mind any code change tbh, but I’d prefer that as an
>> improvement to existing code, and not a part of this patchset.
> 
> Right, but see my argumentation above.

Guess what, I’ll just wait for Thomas to reply here. He knows more DRM than me.
> 
> -- 
> With Best Regards,
> Andy Shevchenko

Re: [PATCH v4 1/2] drm/format-helper: Add conversion from XRGB8888 to BGR888

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 05:00:50PM +0200, andriy.shevchenko@linux.intel.com wrote:
> On Mon, Feb 24, 2025 at 02:54:07PM +0000, Aditya Garg wrote:
> > This conversion helper mimics the existing drm_fb_xrgb8888_to_rgb888 helper
> 
> Not really. See below.
> 
> > > On 24 Feb 2025, at 7:59 PM, andriy.shevchenko@linux.intel.com wrote:
> > > On Mon, Feb 24, 2025 at 01:38:32PM +0000, Aditya Garg wrote:

...

> > >> +static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> > > 
> > > Okay the xrgb8888 is the actual pixel format independently on
> > > the CPU endianess.
> > > 
> > >> +{
> > >> + u8 *dbuf8 = dbuf;
> > >> + const __le32 *sbuf32 = sbuf;
> > > 
> > > But here we assume that sbuf is __le32.
> > > And I think we may benefit from the __be32 there.
> > 
> > So, like drm_fb_xrgb8888_to_rgb888, we are using __le32
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n657
> 
> The rgb888 != bgr888, that's where the byte swapping happens. So, one should
> use __be32 if the other has already been using __le32.

But in both cases it's actually the 24-bit format in 4-byte packets.

I would rewrite both to remove these types as they are just confusing. But it's
probably not your call. So, if you want to stick with __le32, fine, not my call
either :-)

> > >> + unsigned int x;
> > >> + u32 pix;
> > >> +
> > >> + for (x = 0; x < pixels; x++) {
> > >> + pix = le32_to_cpu(sbuf32[x]);
> > >> + /* write red-green-blue to output in little endianness */
> > >> + *dbuf8++ = (pix & 0x00ff0000) >> 16;
> > >> + *dbuf8++ = (pix & 0x0000ff00) >> 8;
> > >> + *dbuf8++ = (pix & 0x000000ff) >> 0;
> > > 
> > > pix = be32_to_cpu(sbuf[4 * x]) >> 8;
> > > put_unaligned_le24(pix, &dbuf[3 * x]);
> > 
> > Again, 
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_format_helper.c?h=v6.14-rc4#n664
> 
> As per above.
> 
> > >> + }
> > > 
> > > Or, after all, this __le32 magic might be not needed at all. Wouldn't the below
> > > be the equivalent
> > > 
> > > static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> > > {
> > > unsigned int x;
> > > u32 pix;
> > > 
> > > for (x = 0; x < pixels; x++) {
> > > /* Read red-green-blue from input in big endianess and... */
> > > pix = get_unaligned_be24(sbuf + x * 4 + 1);
> > > /* ...write it to output in little endianness. */
> > > put_unaligned_le24(pix, dbuf + x * 3);
> > > }
> > > }
> > > 
> > > The comments can even be dropped as the code quite clear about what's going on.


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 1/2] drm/format-helper: Add conversion from XRGB8888 to BGR888

[Thomas Zimmermann]

Hi

Am 24.02.25 um 15:29 schrieb andriy.shevchenko@linux.intel.com:
> On Mon, Feb 24, 2025 at 01:38:32PM +0000, Aditya Garg wrote:
>> From: Kerem Karabay <kekrby@gmail.com>
>>
>> Add XRGB8888 emulation helper for devices that only support BGR888.
> ...
>
>> +static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> Okay the xrgb8888 is the actual pixel format independently on
> the CPU endianess.
>
>> +{
>> +	u8 *dbuf8 = dbuf;
>> +	const __le32 *sbuf32 = sbuf;
> But here we assume that sbuf is __le32.
> And I think we may benefit from the __be32 there.

No, please. XRGB is the logical order. The raw physical byte order for 
DRM formats is always* little endian, hence reversed from the logical 
one. sbuf points to raw memory and is therefore __le32. DRM-format byte 
order is impossible to understand, I know. But that code is correct.

Best regards
Thomas

*) White lie: there's a DRM format flag signalling physical big 
endianess. That isn't the case here. So nothing here should ever 
indicate big endianess.


>
>> +	unsigned int x;
>> +	u32 pix;
>> +
>> +	for (x = 0; x < pixels; x++) {
>> +		pix = le32_to_cpu(sbuf32[x]);
>> +		/* write red-green-blue to output in little endianness */
>> +		*dbuf8++ = (pix & 0x00ff0000) >> 16;
>> +		*dbuf8++ = (pix & 0x0000ff00) >> 8;
>> +		*dbuf8++ = (pix & 0x000000ff) >> 0;
> 		pix = be32_to_cpu(sbuf[4 * x]) >> 8;
> 		put_unaligned_le24(pix, &dbuf[3 * x]);
>
>> +	}
> Or, after all, this __le32 magic might be not needed at all. Wouldn't the below
> be the equivalent
>
> static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> {
> 	unsigned int x;
> 	u32 pix;
>
> 	for (x = 0; x < pixels; x++) {
> 		/* Read red-green-blue from input in big endianess and... */
> 		pix = get_unaligned_be24(sbuf + x * 4 + 1);
> 		/* ...write it to output in little endianness. */
> 		put_unaligned_le24(pix, dbuf + x * 3);
> 	}
> }
>
> The comments can even be dropped as the code quite clear about what's going on.
>
>> +}
> But it's up to you. I don't know which solution gives better code generation
> either.
>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [PATCH v4 1/2] drm/format-helper: Add conversion from XRGB8888 to BGR888

[andriy.shevchenko]

On Tue, Feb 25, 2025 at 08:37:32AM +0100, Thomas Zimmermann wrote:
> Am 24.02.25 um 15:29 schrieb andriy.shevchenko@linux.intel.com:
> > On Mon, Feb 24, 2025 at 01:38:32PM +0000, Aditya Garg wrote:

...

> > > +static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> > Okay the xrgb8888 is the actual pixel format independently on
> > the CPU endianess.
> > 
> > > +{
> > > +	u8 *dbuf8 = dbuf;
> > > +	const __le32 *sbuf32 = sbuf;
> > But here we assume that sbuf is __le32.
> > And I think we may benefit from the __be32 there.
> 
> No, please. XRGB is the logical order. The raw physical byte order for DRM
> formats is always* little endian, hence reversed from the logical one. sbuf
> points to raw memory and is therefore __le32. DRM-format byte order is
> impossible to understand, I know. But that code is correct.

Okay, so it's only about the colour (top-level) layout, the input and output
data is always in little endian?

> *) White lie: there's a DRM format flag signalling physical big endianess.
> That isn't the case here. So nothing here should ever indicate big
> endianess.

But should it indicate the little? To me sounds like neither...

> > > +	unsigned int x;
> > > +	u32 pix;
> > > +
> > > +	for (x = 0; x < pixels; x++) {
> > > +		pix = le32_to_cpu(sbuf32[x]);
> > > +		/* write red-green-blue to output in little endianness */
> > > +		*dbuf8++ = (pix & 0x00ff0000) >> 16;
> > > +		*dbuf8++ = (pix & 0x0000ff00) >> 8;
> > > +		*dbuf8++ = (pix & 0x000000ff) >> 0;
> > 		pix = be32_to_cpu(sbuf[4 * x]) >> 8;
> > 		put_unaligned_le24(pix, &dbuf[3 * x]);
> > 
> > > +	}
> > Or, after all, this __le32 magic might be not needed at all. Wouldn't the below
> > be the equivalent
> > 
> > static void drm_fb_xrgb8888_to_bgr888_line(void *dbuf, const void *sbuf, unsigned int pixels)
> > {
> > 	unsigned int x;
> > 	u32 pix;
> > 
> > 	for (x = 0; x < pixels; x++) {
> > 		/* Read red-green-blue from input in big endianess and... */
> > 		pix = get_unaligned_be24(sbuf + x * 4 + 1);
> > 		/* ...write it to output in little endianness. */
> > 		put_unaligned_le24(pix, dbuf + x * 3);
> > 	}
> > }
> > 
> > The comments can even be dropped as the code quite clear about what's going on.
> > 
> > > +}
> > But it's up to you. I don't know which solution gives better code generation
> > either.

-- 
With Best Regards,
Andy Shevchenko

[PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

From: Kerem Karabay <kekrby@gmail.com>

The Touch Bars found on x86 Macs support two USB configurations: one
where the device presents itself as a HID keyboard and can display
predefined sets of keys, and one where the operating system has full
control over what is displayed.

This commit adds support for the display functionality of the second
configuration. Functionality for the first configuration has been
merged in the HID tree.

Note that this driver has only been tested on T2 Macs, and only includes
the USB device ID for these devices. Testing on T1 Macs would be
appreciated.

Credit goes to Ben (Bingxing) Wang on GitHub for reverse engineering
most of the protocol.

Also, as requested by Andy, I would like to clarify the use of __packed
structs in this driver:

- All the packed structs are aligned except for appletbdrm_msg_information.
- We have to pack appletbdrm_msg_information since it is requirement of
  the protocol.
- We compared binaries compiled by keeping the rest structs __packed and
  not __packed using bloat-o-meter, and __packed was not affecting code
  generation.
- To maintain consistency, rest structs have been kept __packed.

Link: https://github.com/imbushuo/DFRDisplayKm
Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Co-developed-by: Atharva Tiwari <evepolonium@gmail.com>
Signed-off-by: Atharva Tiwari <evepolonium@gmail.com>
Co-developed-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Aun-Ali Zaidi <admin@kodeit.net>
---
v2 ->
- Add the driver to MAINTAINERS.
- Allocate memory for request and response in plane's atomic-check helper
- Void the use of drm_fb_blit()
- Implement atomic_disable
- Make PRIME work
- Remove the date field from struct drm_driver 
- intersect damage with dst_clip
- Register DRM device in appletbdrm_probe
- Clear the display as the final call in probe
- Select hid_multitouch as well in kconfig

v3 ->
- Change commit message to credit Ben (Bingxing) Wang

v4 ->
- Use "Link:" in commit message
- Specify why __packed has been used in commit message
- Use %p4cc instead of %p4ch for errors
- Add myself to Maintainers
- Remove #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
- Add missing header files
- Use return 0; instead of return ret; in static int appletbdrm_send_request
- Better errno types used in appletbdrm_read_response
- Use BITS_TO_BYTES() to convert APPLETBDRM_BITS_PER_PIXEL to bytes
- Remove redundant else in plane_helper_atomic_check
- Remove unnecessary use of 0xff in request->msg_id = timestamp & 0xff;
- Remove duplicated struct device in struct appletbdrm_device
- clear frames_size and request_size as well in primary_plane_helper_atomic_update
- Allocate using kzalloc instead of kmemdup
- Use drm_err() instead of dev_err_probe()
- Avoid clearing drm->mode_config.min_width and height to 0
- Use put_device() to release the DMA device in appletbdrm_disconnect

 MAINTAINERS                       |   8 +
 drivers/gpu/drm/tiny/Kconfig      |  14 +
 drivers/gpu/drm/tiny/Makefile     |   1 +
 drivers/gpu/drm/tiny/appletbdrm.c | 835 ++++++++++++++++++++++++++++++
 4 files changed, 858 insertions(+)
 create mode 100644 drivers/gpu/drm/tiny/appletbdrm.c

diff --git a/MAINTAINERS b/MAINTAINERS
index efee40ea5..f7c97eb24 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7148,6 +7148,14 @@ S:	Supported
 T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
 F:	drivers/gpu/drm/sun4i/sun8i*
 
+DRM DRIVER FOR APPLE TOUCH BARS
+M:	Aun-Ali Zaidi <admin@kodeit.net>
+M:	Aditya Garg <gargaditya08@live.com>
+L:	dri-devel@lists.freedesktop.org
+S:	Maintained
+T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
+F:	drivers/gpu/drm/tiny/appletbdrm.c
+
 DRM DRIVER FOR ARM PL111 CLCD
 M:	Linus Walleij <linus.walleij@linaro.org>
 S:	Maintained
diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
index 94cbdb133..25471791c 100644
--- a/drivers/gpu/drm/tiny/Kconfig
+++ b/drivers/gpu/drm/tiny/Kconfig
@@ -1,5 +1,19 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
+config DRM_APPLETBDRM
+	tristate "DRM support for Apple Touch Bars"
+	depends on DRM && USB && MMU
+	select DRM_GEM_SHMEM_HELPER
+	select DRM_KMS_HELPER
+	select HID_APPLETB_BL
+	select HID_MULTITOUCH
+	help
+	  Say Y here if you want support for the display of Touch Bars on x86
+	  MacBook Pros.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called appletbdrm.
+
 config DRM_ARCPGU
 	tristate "ARC PGU"
 	depends on DRM && OF
diff --git a/drivers/gpu/drm/tiny/Makefile b/drivers/gpu/drm/tiny/Makefile
index 60816d2eb..0a3a7837a 100644
--- a/drivers/gpu/drm/tiny/Makefile
+++ b/drivers/gpu/drm/tiny/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
+obj-$(CONFIG_DRM_APPLETBDRM)		+= appletbdrm.o
 obj-$(CONFIG_DRM_ARCPGU)		+= arcpgu.o
 obj-$(CONFIG_DRM_BOCHS)			+= bochs.o
 obj-$(CONFIG_DRM_CIRRUS_QEMU)		+= cirrus-qemu.o
diff --git a/drivers/gpu/drm/tiny/appletbdrm.c b/drivers/gpu/drm/tiny/appletbdrm.c
new file mode 100644
index 000000000..59a2b20d4
--- /dev/null
+++ b/drivers/gpu/drm/tiny/appletbdrm.c
@@ -0,0 +1,835 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Apple Touch Bar DRM Driver
+ *
+ * Copyright (c) 2023 Kerem Karabay <kekrby@gmail.com>
+ */
+
+#include <linux/align.h>
+#include <linux/array_size.h>
+#include <linux/bitops.h>
+#include <linux/bug.h>
+#include <linux/container_of.h>
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/overflow.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/unaligned.h>
+#include <linux/usb.h>
+
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_encoder.h>
+#include <drm/drm_format_helper.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_framebuffer.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_plane.h>
+#include <drm/drm_probe_helper.h>
+
+#define __APPLETBDRM_MSG_STR4(str4)	((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
+#define __APPLETBDRM_MSG_TOK4(tok4)	__APPLETBDRM_MSG_STR4(#tok4)
+
+#define APPLETBDRM_PIXEL_FORMAT		__APPLETBDRM_MSG_TOK4(RGBA) /* The actual format is BGR888 */
+#define APPLETBDRM_BITS_PER_PIXEL	24
+
+#define APPLETBDRM_MSG_CLEAR_DISPLAY	__APPLETBDRM_MSG_TOK4(CLRD)
+#define APPLETBDRM_MSG_GET_INFORMATION	__APPLETBDRM_MSG_TOK4(GINF)
+#define APPLETBDRM_MSG_UPDATE_COMPLETE	__APPLETBDRM_MSG_TOK4(UDCL)
+#define APPLETBDRM_MSG_SIGNAL_READINESS	__APPLETBDRM_MSG_TOK4(REDY)
+
+#define APPLETBDRM_BULK_MSG_TIMEOUT	1000
+
+#define drm_to_adev(_drm)		container_of(_drm, struct appletbdrm_device, drm)
+#define adev_to_udev(adev)		interface_to_usbdev(to_usb_interface(adev->dev))
+
+struct appletbdrm_msg_request_header {
+	__le16 unk_00;
+	__le16 unk_02;
+	__le32 unk_04;
+	__le32 unk_08;
+	__le32 size;
+} __packed;
+
+struct appletbdrm_msg_response_header {
+	u8 unk_00[16];
+	__le32 msg;
+} __packed;
+
+struct appletbdrm_msg_simple_request {
+	struct appletbdrm_msg_request_header header;
+	__le32 msg;
+	u8 unk_14[8];
+	__le32 size;
+} __packed;
+
+struct appletbdrm_msg_information {
+	struct appletbdrm_msg_response_header header;
+	u8 unk_14[12];
+	__le32 width;
+	__le32 height;
+	u8 bits_per_pixel;
+	__le32 bytes_per_row;
+	__le32 orientation;
+	__le32 bitmap_info;
+	__le32 pixel_format;
+	__le32 width_inches;	/* floating point */
+	__le32 height_inches;	/* floating point */
+} __packed;
+
+struct appletbdrm_frame {
+	__le16 begin_x;
+	__le16 begin_y;
+	__le16 width;
+	__le16 height;
+	__le32 buf_size;
+	u8 buf[];
+} __packed;
+
+struct appletbdrm_fb_request_footer {
+	u8 unk_00[12];
+	__le32 unk_0c;
+	u8 unk_10[12];
+	__le32 unk_1c;
+	__le64 timestamp;
+	u8 unk_28[12];
+	__le32 unk_34;
+	u8 unk_38[20];
+	__le32 unk_4c;
+} __packed;
+
+struct appletbdrm_fb_request {
+	struct appletbdrm_msg_request_header header;
+	__le16 unk_10;
+	u8 msg_id;
+	u8 unk_13[29];
+	/*
+	 * Contents of `data`:
+	 * - struct appletbdrm_frame frames[];
+	 * - struct appletbdrm_fb_request_footer footer;
+	 * - padding to make the total size a multiple of 16
+	 */
+	u8 data[];
+} __packed;
+
+struct appletbdrm_fb_request_response {
+	struct appletbdrm_msg_response_header header;
+	u8 unk_14[12];
+	__le64 timestamp;
+} __packed;
+
+struct appletbdrm_device {
+	struct device *dev;
+
+	unsigned int in_ep;
+	unsigned int out_ep;
+
+	unsigned int width;
+	unsigned int height;
+
+	struct drm_device drm;
+	struct drm_display_mode mode;
+	struct drm_connector connector;
+	struct drm_plane primary_plane;
+	struct drm_crtc crtc;
+	struct drm_encoder encoder;
+};
+
+struct appletbdrm_plane_state {
+	struct drm_shadow_plane_state base;
+	struct appletbdrm_fb_request *request;
+	struct appletbdrm_fb_request_response *response;
+	size_t request_size;
+	size_t frames_size;
+};
+
+static inline struct appletbdrm_plane_state *to_appletbdrm_plane_state(struct drm_plane_state *state)
+{
+	return container_of(state, struct appletbdrm_plane_state, base.base);
+}
+
+static int appletbdrm_send_request(struct appletbdrm_device *adev,
+				   struct appletbdrm_msg_request_header *request, size_t size)
+{
+	struct usb_device *udev = adev_to_udev(adev);
+	struct drm_device *drm = &adev->drm;
+	int ret, actual_size;
+
+	ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, adev->out_ep),
+			   request, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT);
+	if (ret) {
+		drm_err(drm, "Failed to send message (%d)\n", ret);
+		return ret;
+	}
+
+	if (actual_size != size) {
+		drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
+			actual_size, size);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int appletbdrm_read_response(struct appletbdrm_device *adev,
+				    struct appletbdrm_msg_response_header *response,
+				    size_t size, __le32 expected_response)
+{
+	struct usb_device *udev = adev_to_udev(adev);
+	struct drm_device *drm = &adev->drm;
+	int ret, actual_size;
+	bool readiness_signal_received = false;
+
+retry:
+	ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, adev->in_ep),
+			   response, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT);
+	if (ret) {
+		drm_err(drm, "Failed to read response (%d)\n", ret);
+		return ret;
+	}
+
+	/*
+	 * The device responds to the first request sent in a particular
+	 * timeframe after the USB device configuration is set with a readiness
+	 * signal, in which case the response should be read again
+	 */
+	if (response->msg == APPLETBDRM_MSG_SIGNAL_READINESS) {
+		if (!readiness_signal_received) {
+			readiness_signal_received = true;
+			goto retry;
+		}
+
+		drm_err(drm, "Encountered unexpected readiness signal\n");
+		return -EINTR;
+	}
+
+	if (actual_size != size) {
+		drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
+			actual_size, size);
+		return -EBADMSG;
+	}
+
+	if (response->msg != expected_response) {
+		drm_err(drm, "Unexpected response from device (expected %p4cc found %p4cc)\n",
+			&expected_response, &response->msg);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int appletbdrm_send_msg(struct appletbdrm_device *adev, __le32 msg)
+{
+	struct appletbdrm_msg_simple_request *request;
+	int ret;
+
+	request = kzalloc(sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	request->header.unk_00 = cpu_to_le16(2);
+	request->header.unk_02 = cpu_to_le16(0x1512);
+	request->header.size = cpu_to_le32(sizeof(*request) - sizeof(request->header));
+	request->msg = msg;
+	request->size = request->header.size;
+
+	ret = appletbdrm_send_request(adev, &request->header, sizeof(*request));
+
+	kfree(request);
+
+	return ret;
+}
+
+static int appletbdrm_clear_display(struct appletbdrm_device *adev)
+{
+	return appletbdrm_send_msg(adev, APPLETBDRM_MSG_CLEAR_DISPLAY);
+}
+
+static int appletbdrm_signal_readiness(struct appletbdrm_device *adev)
+{
+	return appletbdrm_send_msg(adev, APPLETBDRM_MSG_SIGNAL_READINESS);
+}
+
+static int appletbdrm_get_information(struct appletbdrm_device *adev)
+{
+	struct appletbdrm_msg_information *info;
+	struct drm_device *drm = &adev->drm;
+	u8 bits_per_pixel;
+	__le32 pixel_format;
+	int ret;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	ret = appletbdrm_send_msg(adev, APPLETBDRM_MSG_GET_INFORMATION);
+	if (ret)
+		return ret;
+
+	ret = appletbdrm_read_response(adev, &info->header, sizeof(*info),
+				       APPLETBDRM_MSG_GET_INFORMATION);
+	if (ret)
+		goto free_info;
+
+	bits_per_pixel = info->bits_per_pixel;
+	pixel_format = get_unaligned(&info->pixel_format);
+
+	adev->width = get_unaligned_le32(&info->width);
+	adev->height = get_unaligned_le32(&info->height);
+
+	if (bits_per_pixel != APPLETBDRM_BITS_PER_PIXEL) {
+		drm_err(drm, "Encountered unexpected bits per pixel value (%d)\n", bits_per_pixel);
+		ret = -EINVAL;
+		goto free_info;
+	}
+
+	if (pixel_format != APPLETBDRM_PIXEL_FORMAT) {
+		drm_err(drm, "Encountered unknown pixel format (%p4cc)\n", &pixel_format);
+		ret = -EINVAL;
+		goto free_info;
+	}
+
+free_info:
+	kfree(info);
+
+	return ret;
+}
+
+static u32 rect_size(struct drm_rect *rect)
+{
+	return drm_rect_width(rect) * drm_rect_height(rect) *
+		(BITS_TO_BYTES(APPLETBDRM_BITS_PER_PIXEL));
+}
+
+static int appletbdrm_connector_helper_get_modes(struct drm_connector *connector)
+{
+	struct appletbdrm_device *adev = drm_to_adev(connector->dev);
+
+	return drm_connector_helper_get_modes_fixed(connector, &adev->mode);
+}
+
+static const u32 appletbdrm_primary_plane_formats[] = {
+	DRM_FORMAT_BGR888,
+	DRM_FORMAT_XRGB8888, /* emulated */
+};
+
+static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
+						   struct drm_atomic_state *state)
+{
+	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
+	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
+	struct drm_crtc *new_crtc = new_plane_state->crtc;
+	struct drm_crtc_state *new_crtc_state = NULL;
+	struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(new_plane_state);
+	struct drm_atomic_helper_damage_iter iter;
+	struct drm_rect damage;
+	size_t frames_size = 0;
+	size_t request_size;
+	int ret;
+
+	if (new_crtc)
+		new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
+
+	ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
+						  DRM_PLANE_NO_SCALING,
+						  DRM_PLANE_NO_SCALING,
+						  false, false);
+	if (ret)
+		return ret;
+
+	if (!new_plane_state->visible)
+		return 0;
+
+	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, new_plane_state);
+	drm_atomic_for_each_plane_damage(&iter, &damage) {
+		frames_size += struct_size((struct appletbdrm_frame *)0, buf, rect_size(&damage));
+	}
+
+	if (!frames_size)
+		return 0;
+
+	request_size = ALIGN(sizeof(struct appletbdrm_fb_request) +
+		       frames_size +
+		       sizeof(struct appletbdrm_fb_request_footer), 16);
+
+	appletbdrm_state->request = kzalloc(request_size, GFP_KERNEL);
+
+	if (!appletbdrm_state->request)
+		return -ENOMEM;
+
+	appletbdrm_state->response = kzalloc(sizeof(*appletbdrm_state->response), GFP_KERNEL);
+
+	if (!appletbdrm_state->response)
+		return -ENOMEM;
+
+	appletbdrm_state->request_size = request_size;
+	appletbdrm_state->frames_size = frames_size;
+
+	return 0;
+}
+
+static int appletbdrm_flush_damage(struct appletbdrm_device *adev,
+				   struct drm_plane_state *old_state,
+				   struct drm_plane_state *state)
+{
+	struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state);
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
+	struct appletbdrm_fb_request_response *response = appletbdrm_state->response;
+	struct appletbdrm_fb_request_footer *footer;
+	struct drm_atomic_helper_damage_iter iter;
+	struct drm_framebuffer *fb = state->fb;
+	struct appletbdrm_fb_request *request = appletbdrm_state->request;
+	struct drm_device *drm = &adev->drm;
+	struct appletbdrm_frame *frame;
+	u64 timestamp = ktime_get_ns();
+	struct drm_rect damage;
+	size_t frames_size = appletbdrm_state->frames_size;
+	size_t request_size = appletbdrm_state->request_size;
+	int ret;
+
+	if (!frames_size)
+		return 0;
+
+	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
+	if (ret) {
+		drm_err(drm, "Failed to start CPU framebuffer access (%d)\n", ret);
+		goto end_fb_cpu_access;
+	}
+
+	request->header.unk_00 = cpu_to_le16(2);
+	request->header.unk_02 = cpu_to_le16(0x12);
+	request->header.unk_04 = cpu_to_le32(9);
+	request->header.size = cpu_to_le32(request_size - sizeof(request->header));
+	request->unk_10 = cpu_to_le16(1);
+	request->msg_id = timestamp;
+
+	frame = (struct appletbdrm_frame *)request->data;
+
+	drm_atomic_helper_damage_iter_init(&iter, old_state, state);
+	drm_atomic_for_each_plane_damage(&iter, &damage) {
+		struct drm_rect dst_clip = state->dst;
+		struct iosys_map dst = IOSYS_MAP_INIT_VADDR(frame->buf);
+		u32 buf_size = rect_size(&damage);
+
+		if (!drm_rect_intersect(&dst_clip, &damage))
+			continue;
+
+		/*
+		 * The coordinates need to be translated to the coordinate
+		 * system the device expects, see the comment in
+		 * appletbdrm_setup_mode_config
+		 */
+		frame->begin_x = cpu_to_le16(damage.y1);
+		frame->begin_y = cpu_to_le16(adev->height - damage.x2);
+		frame->width = cpu_to_le16(drm_rect_height(&damage));
+		frame->height = cpu_to_le16(drm_rect_width(&damage));
+		frame->buf_size = cpu_to_le32(buf_size);
+
+		switch (fb->format->format) {
+		case DRM_FORMAT_XRGB8888:
+			drm_fb_xrgb8888_to_bgr888(&dst, NULL, &shadow_plane_state->data[0], fb, &damage, &shadow_plane_state->fmtcnv_state);
+			break;
+		default:
+			drm_fb_memcpy(&dst, NULL, &shadow_plane_state->data[0], fb, &damage);
+			break;
+		}
+
+		frame = (void *)frame + struct_size(frame, buf, buf_size);
+	}
+
+	footer = (struct appletbdrm_fb_request_footer *)&request->data[frames_size];
+
+	footer->unk_0c = cpu_to_le32(0xfffe);
+	footer->unk_1c = cpu_to_le32(0x80001);
+	footer->unk_34 = cpu_to_le32(0x80002);
+	footer->unk_4c = cpu_to_le32(0xffff);
+	footer->timestamp = cpu_to_le64(timestamp);
+
+	ret = appletbdrm_send_request(adev, &request->header, request_size);
+	if (ret)
+		goto end_fb_cpu_access;
+
+	ret = appletbdrm_read_response(adev, &response->header, sizeof(*response),
+				       APPLETBDRM_MSG_UPDATE_COMPLETE);
+	if (ret)
+		goto end_fb_cpu_access;
+
+	if (response->timestamp != footer->timestamp) {
+		drm_err(drm, "Response timestamp (%llu) doesn't match request timestamp (%llu)\n",
+			le64_to_cpu(response->timestamp), timestamp);
+		goto end_fb_cpu_access;
+	}
+
+end_fb_cpu_access:
+	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
+
+	return ret;
+}
+
+static void appletbdrm_primary_plane_helper_atomic_update(struct drm_plane *plane,
+						     struct drm_atomic_state *old_state)
+{
+	struct appletbdrm_device *adev = drm_to_adev(plane->dev);
+	struct drm_device *drm = plane->dev;
+	struct drm_plane_state *plane_state = plane->state;
+	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(old_state, plane);
+	int idx;
+
+	if (!drm_dev_enter(drm, &idx))
+		return;
+
+	appletbdrm_flush_damage(adev, old_plane_state, plane_state);
+
+	drm_dev_exit(idx);
+}
+
+static void appletbdrm_primary_plane_helper_atomic_disable(struct drm_plane *plane,
+							   struct drm_atomic_state *state)
+{
+	struct drm_device *dev = plane->dev;
+	struct appletbdrm_device *adev = drm_to_adev(dev);
+	int idx;
+
+	if (!drm_dev_enter(dev, &idx))
+		return;
+
+	appletbdrm_clear_display(adev);
+
+	drm_dev_exit(idx);
+}
+
+static void appletbdrm_primary_plane_reset(struct drm_plane *plane)
+{
+	struct appletbdrm_plane_state *appletbdrm_state;
+
+	WARN_ON(plane->state);
+
+	appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL);
+	if (!appletbdrm_state)
+		return;
+
+	__drm_gem_reset_shadow_plane(plane, &appletbdrm_state->base);
+}
+
+static struct drm_plane_state *appletbdrm_primary_plane_duplicate_state(struct drm_plane *plane)
+{
+	struct drm_shadow_plane_state *new_shadow_plane_state;
+	struct appletbdrm_plane_state *old_appletbdrm_state;
+	struct appletbdrm_plane_state *appletbdrm_state;
+
+	if (WARN_ON(!plane->state))
+		return NULL;
+
+	old_appletbdrm_state = to_appletbdrm_plane_state(plane->state);
+	appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL);
+	if (!appletbdrm_state)
+		return NULL;
+
+	/* Request and response are not duplicated and are allocated in .atomic_check */
+	appletbdrm_state->request = NULL;
+	appletbdrm_state->response = NULL;
+
+	appletbdrm_state->request_size = 0;
+	appletbdrm_state->frames_size = 0;
+
+	new_shadow_plane_state = &appletbdrm_state->base;
+
+	__drm_gem_duplicate_shadow_plane_state(plane, new_shadow_plane_state);
+
+	return &new_shadow_plane_state->base;
+}
+
+static void appletbdrm_primary_plane_destroy_state(struct drm_plane *plane,
+						   struct drm_plane_state *state)
+{
+	struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state);
+
+	kfree(appletbdrm_state->request);
+	kfree(appletbdrm_state->response);
+
+	__drm_gem_destroy_shadow_plane_state(&appletbdrm_state->base);
+
+	kfree(appletbdrm_state);
+}
+
+static const struct drm_plane_helper_funcs appletbdrm_primary_plane_helper_funcs = {
+	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
+	.atomic_check = appletbdrm_primary_plane_helper_atomic_check,
+	.atomic_update = appletbdrm_primary_plane_helper_atomic_update,
+	.atomic_disable = appletbdrm_primary_plane_helper_atomic_disable,
+};
+
+static const struct drm_plane_funcs appletbdrm_primary_plane_funcs = {
+	.update_plane = drm_atomic_helper_update_plane,
+	.disable_plane = drm_atomic_helper_disable_plane,
+	.reset = appletbdrm_primary_plane_reset,
+	.atomic_duplicate_state = appletbdrm_primary_plane_duplicate_state,
+	.atomic_destroy_state = appletbdrm_primary_plane_destroy_state,
+	.destroy = drm_plane_cleanup,
+};
+
+static enum drm_mode_status appletbdrm_crtc_helper_mode_valid(struct drm_crtc *crtc,
+							  const struct drm_display_mode *mode)
+{
+	struct appletbdrm_device *adev = drm_to_adev(crtc->dev);
+
+	return drm_crtc_helper_mode_valid_fixed(crtc, mode, &adev->mode);
+}
+
+static const struct drm_mode_config_funcs appletbdrm_mode_config_funcs = {
+	.fb_create = drm_gem_fb_create_with_dirty,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+static const struct drm_connector_funcs appletbdrm_connector_funcs = {
+	.reset = drm_atomic_helper_connector_reset,
+	.destroy = drm_connector_cleanup,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+};
+
+static const struct drm_connector_helper_funcs appletbdrm_connector_helper_funcs = {
+	.get_modes = appletbdrm_connector_helper_get_modes,
+};
+
+static const struct drm_crtc_helper_funcs appletbdrm_crtc_helper_funcs = {
+	.mode_valid = appletbdrm_crtc_helper_mode_valid,
+};
+
+static const struct drm_crtc_funcs appletbdrm_crtc_funcs = {
+	.reset = drm_atomic_helper_crtc_reset,
+	.destroy = drm_crtc_cleanup,
+	.set_config = drm_atomic_helper_set_config,
+	.page_flip = drm_atomic_helper_page_flip,
+	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
+};
+
+static const struct drm_encoder_funcs appletbdrm_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
+static struct drm_gem_object *appletbdrm_driver_gem_prime_import(struct drm_device *dev,
+								 struct dma_buf *dma_buf)
+{
+	struct appletbdrm_device *adev = drm_to_adev(dev);
+
+	if (!adev->dev)
+		return ERR_PTR(-ENODEV);
+
+	return drm_gem_prime_import_dev(dev, dma_buf, adev->dev);
+}
+
+DEFINE_DRM_GEM_FOPS(appletbdrm_drm_fops);
+
+static const struct drm_driver appletbdrm_drm_driver = {
+	DRM_GEM_SHMEM_DRIVER_OPS,
+	.gem_prime_import	= appletbdrm_driver_gem_prime_import,
+	.name			= "appletbdrm",
+	.desc			= "Apple Touch Bar DRM Driver",
+	.major			= 1,
+	.minor			= 0,
+	.driver_features	= DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
+	.fops			= &appletbdrm_drm_fops,
+};
+
+static int appletbdrm_setup_mode_config(struct appletbdrm_device *adev)
+{
+	struct drm_connector *connector = &adev->connector;
+	struct drm_plane *primary_plane;
+	struct drm_crtc *crtc;
+	struct drm_encoder *encoder;
+	struct drm_device *drm = &adev->drm;
+	int ret;
+
+	ret = drmm_mode_config_init(drm);
+	if (ret) {
+		drm_err(drm, "Failed to initialize mode configuration\n");
+		return ret;
+	}
+
+	primary_plane = &adev->primary_plane;
+	ret = drm_universal_plane_init(drm, primary_plane, 0,
+				       &appletbdrm_primary_plane_funcs,
+				       appletbdrm_primary_plane_formats,
+				       ARRAY_SIZE(appletbdrm_primary_plane_formats),
+				       NULL,
+				       DRM_PLANE_TYPE_PRIMARY, NULL);
+	if (ret) {
+		drm_err(drm, "Failed to initialize universal plane object\n");
+		return ret;
+	}
+
+	drm_plane_helper_add(primary_plane, &appletbdrm_primary_plane_helper_funcs);
+	drm_plane_enable_fb_damage_clips(primary_plane);
+
+	crtc = &adev->crtc;
+	ret = drm_crtc_init_with_planes(drm, crtc, primary_plane, NULL,
+					&appletbdrm_crtc_funcs, NULL);
+	if (ret) {
+		drm_err(drm, "Failed to initialize CRTC object\n");
+		return ret;
+	}
+
+	drm_crtc_helper_add(crtc, &appletbdrm_crtc_helper_funcs);
+
+	encoder = &adev->encoder;
+	ret = drm_encoder_init(drm, encoder, &appletbdrm_encoder_funcs,
+			       DRM_MODE_ENCODER_DAC, NULL);
+	if (ret) {
+		drm_err(drm, "Failed to initialize encoder\n");
+		return ret;
+	}
+
+	encoder->possible_crtcs = drm_crtc_mask(crtc);
+
+	/*
+	 * The coordinate system used by the device is different from the
+	 * coordinate system of the framebuffer in that the x and y axes are
+	 * swapped, and that the y axis is inverted; so what the device reports
+	 * as the height is actually the width of the framebuffer and vice
+	 * versa
+	 */
+	drm->mode_config.max_width = max(adev->height, DRM_SHADOW_PLANE_MAX_WIDTH);
+	drm->mode_config.max_height = max(adev->width, DRM_SHADOW_PLANE_MAX_HEIGHT);
+	drm->mode_config.preferred_depth = APPLETBDRM_BITS_PER_PIXEL;
+	drm->mode_config.funcs = &appletbdrm_mode_config_funcs;
+
+	adev->mode = (struct drm_display_mode) {
+		DRM_MODE_INIT(60, adev->height, adev->width,
+			      DRM_MODE_RES_MM(adev->height, 218),
+			      DRM_MODE_RES_MM(adev->width, 218))
+	};
+
+	ret = drm_connector_init(drm, connector,
+				 &appletbdrm_connector_funcs, DRM_MODE_CONNECTOR_USB);
+	if (ret) {
+		drm_err(drm, "Failed to initialize connector\n");
+		return ret;
+	}
+
+	drm_connector_helper_add(connector, &appletbdrm_connector_helper_funcs);
+
+	ret = drm_connector_set_panel_orientation(connector,
+						  DRM_MODE_PANEL_ORIENTATION_RIGHT_UP);
+	if (ret) {
+		drm_err(drm, "Failed to set panel orientation\n");
+		return ret;
+	}
+
+	connector->display_info.non_desktop = true;
+	ret = drm_object_property_set_value(&connector->base,
+					    drm->mode_config.non_desktop_property, true);
+	if (ret) {
+		drm_err(drm, "Failed to set non-desktop property\n");
+		return ret;
+	}
+
+	ret = drm_connector_attach_encoder(connector, encoder);
+
+	if (ret) {
+		drm_err(drm, "Failed to initialize simple display pipe\n");
+		return ret;
+	}
+
+	drm_mode_config_reset(drm);
+
+	return 0;
+}
+
+static int appletbdrm_probe(struct usb_interface *intf,
+			    const struct usb_device_id *id)
+{
+	struct usb_endpoint_descriptor *bulk_in, *bulk_out;
+	struct device *dev = &intf->dev;
+	struct appletbdrm_device *adev;
+	struct drm_device *drm;
+	int ret;
+
+	ret = usb_find_common_endpoints(intf->cur_altsetting, &bulk_in, &bulk_out, NULL, NULL);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to find bulk endpoints\n");
+
+	adev = devm_drm_dev_alloc(dev, &appletbdrm_drm_driver, struct appletbdrm_device, drm);
+	if (IS_ERR(adev))
+		return PTR_ERR(adev);
+
+	adev->dev = dev;
+	adev->in_ep = bulk_in->bEndpointAddress;
+	adev->out_ep = bulk_out->bEndpointAddress;
+
+	drm = &adev->drm;
+
+	usb_set_intfdata(intf, adev);
+
+	ret = appletbdrm_get_information(adev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get display information\n");
+
+	ret = appletbdrm_signal_readiness(adev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to signal readiness\n");
+
+	ret = appletbdrm_setup_mode_config(adev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to setup mode config\n");
+
+	ret = drm_dev_register(drm, 0);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register DRM device\n");
+
+	ret = appletbdrm_clear_display(adev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to clear display\n");
+
+	return 0;
+}
+
+static void appletbdrm_disconnect(struct usb_interface *intf)
+{
+	struct appletbdrm_device *adev = usb_get_intfdata(intf);
+	struct drm_device *drm = &adev->drm;
+
+	put_device(adev->dev);
+	drm_dev_unplug(drm);
+	drm_atomic_helper_shutdown(drm);
+}
+
+static void appletbdrm_shutdown(struct usb_interface *intf)
+{
+	struct appletbdrm_device *adev = usb_get_intfdata(intf);
+
+	/*
+	 * The framebuffer needs to be cleared on shutdown since its content
+	 * persists across boots
+	 */
+	drm_atomic_helper_shutdown(&adev->drm);
+}
+
+static const struct usb_device_id appletbdrm_usb_id_table[] = {
+	{ USB_DEVICE_INTERFACE_CLASS(0x05ac, 0x8302, USB_CLASS_AUDIO_VIDEO) },
+	{}
+};
+MODULE_DEVICE_TABLE(usb, appletbdrm_usb_id_table);
+
+static struct usb_driver appletbdrm_usb_driver = {
+	.name		= "appletbdrm",
+	.probe		= appletbdrm_probe,
+	.disconnect	= appletbdrm_disconnect,
+	.shutdown	= appletbdrm_shutdown,
+	.id_table	= appletbdrm_usb_id_table,
+};
+module_usb_driver(appletbdrm_usb_driver);
+
+MODULE_AUTHOR("Kerem Karabay <kekrby@gmail.com>");
+MODULE_DESCRIPTION("Apple Touch Bar DRM Driver");
+MODULE_LICENSE("GPL");
-- 
2.43.0

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
> From: Kerem Karabay <kekrby@gmail.com>
> 
> The Touch Bars found on x86 Macs support two USB configurations: one
> where the device presents itself as a HID keyboard and can display
> predefined sets of keys, and one where the operating system has full
> control over what is displayed.
> 
> This commit adds support for the display functionality of the second
> configuration. Functionality for the first configuration has been
> merged in the HID tree.
> 
> Note that this driver has only been tested on T2 Macs, and only includes
> the USB device ID for these devices. Testing on T1 Macs would be
> appreciated.
> 
> Credit goes to Ben (Bingxing) Wang on GitHub for reverse engineering
> most of the protocol.
> 
> Also, as requested by Andy, I would like to clarify the use of __packed
> structs in this driver:
> 
> - All the packed structs are aligned except for appletbdrm_msg_information.
> - We have to pack appletbdrm_msg_information since it is requirement of
>   the protocol.
> - We compared binaries compiled by keeping the rest structs __packed and
>   not __packed using bloat-o-meter, and __packed was not affecting code
>   generation.
> - To maintain consistency, rest structs have been kept __packed.

...

> +#define __APPLETBDRM_MSG_STR4(str4)	((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))

As commented previously this is quite strange what's going on with endianess in
this driver. Especially the above weirdness when get_unaligned_be32() is being
open coded and force-cast to __le32.

...

> +struct appletbdrm_msg_information {
> +	struct appletbdrm_msg_response_header header;
> +	u8 unk_14[12];
> +	__le32 width;
> +	__le32 height;
> +	u8 bits_per_pixel;
> +	__le32 bytes_per_row;
> +	__le32 orientation;
> +	__le32 bitmap_info;
> +	__le32 pixel_format;
> +	__le32 width_inches;	/* floating point */
> +	__le32 height_inches;	/* floating point */
> +} __packed;

Haven't looked deeply into the protocol, but still makes me think that
the above (since it's the only __packed data type required) might be simply
depicted wrongly w.r.t. endianess / data types in use. It might be that
the data types have something combined and / or different types.

Do I understand correctly that the protocol was basically reverse-engineered?

...

> +	/*
> +	 * The coordinate system used by the device is different from the
> +	 * coordinate system of the framebuffer in that the x and y axes are
> +	 * swapped, and that the y axis is inverted; so what the device reports
> +	 * as the height is actually the width of the framebuffer and vice
> +	 * versa

Missing period.

> +	 */

...

Otherwise it's nice tiny driver.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
>> From: Kerem Karabay <kekrby@gmail.com>
>> 
>> The Touch Bars found on x86 Macs support two USB configurations: one
>> where the device presents itself as a HID keyboard and can display
>> predefined sets of keys, and one where the operating system has full
>> control over what is displayed.
>> 
>> This commit adds support for the display functionality of the second
>> configuration. Functionality for the first configuration has been
>> merged in the HID tree.
>> 
>> Note that this driver has only been tested on T2 Macs, and only includes
>> the USB device ID for these devices. Testing on T1 Macs would be
>> appreciated.
>> 
>> Credit goes to Ben (Bingxing) Wang on GitHub for reverse engineering
>> most of the protocol.
>> 
>> Also, as requested by Andy, I would like to clarify the use of __packed
>> structs in this driver:
>> 
>> - All the packed structs are aligned except for appletbdrm_msg_information.
>> - We have to pack appletbdrm_msg_information since it is requirement of
>>  the protocol.
>> - We compared binaries compiled by keeping the rest structs __packed and
>>  not __packed using bloat-o-meter, and __packed was not affecting code
>>  generation.
>> - To maintain consistency, rest structs have been kept __packed.
> 
> ...
> 
>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> 
> As commented previously this is quite strange what's going on with endianess in
> this driver. Especially the above weirdness when get_unaligned_be32() is being
> open coded and force-cast to __le32.

I would assume it was also mimicked from the Windows driver, though I haven't really tried exploring this there.

I’d rather be happy if you give me code change suggestions and let me review and test them

> 
> ...
> 
>> +struct appletbdrm_msg_information {
>> + struct appletbdrm_msg_response_header header;
>> + u8 unk_14[12];
>> + __le32 width;
>> + __le32 height;
>> + u8 bits_per_pixel;
>> + __le32 bytes_per_row;
>> + __le32 orientation;
>> + __le32 bitmap_info;
>> + __le32 pixel_format;
>> + __le32 width_inches; /* floating point */
>> + __le32 height_inches; /* floating point */
>> +} __packed;
> 
> Haven't looked deeply into the protocol, but still makes me think that
> the above (since it's the only __packed data type required) might be simply
> depicted wrongly w.r.t. endianess / data types in use. It might be that
> the data types have something combined and / or different types.
> 
> Do I understand correctly that the protocol was basically reverse-engineered?

Yes. Although it was reverse engineered by the person who wrote the Windows driver. The author has just made a Linux port.
So, as far as how is was reverse engineered, it not really possible for me to explain. I don't even have any contact with the person who wrote the Windows driver. The only point here would be to myself RE the hardware again, which tbh isn't very motivating, considering that we have a working driver.
> 
> ...
> 
>> + /*
>> +  * The coordinate system used by the device is different from the
>> +  * coordinate system of the framebuffer in that the x and y axes are
>> +  * swapped, and that the y axis is inverted; so what the device reports
>> +  * as the height is actually the width of the framebuffer and vice
>> +  * versa
> 
> Missing period.

Alright. For some reason (a mistake on my part), some dev_err_probe were also still left in this version. I’ll send a v5.
> 
>> +  */
> 
> ...
> 
> Otherwise it's nice tiny driver.
> 
> -- 
> With Best Regards,
> Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
> > On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
> > On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:

...

> >> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> > 
> > As commented previously this is quite strange what's going on with endianess in
> > this driver. Especially the above weirdness when get_unaligned_be32() is being
> > open coded and force-cast to __le32.
> 
> I would assume it was also mimicked from the Windows driver, though I haven't
> really tried exploring this there.
> 
> I’d rather be happy if you give me code change suggestions and let me review
> and test them

For the starter I would do the following for all related constants and
drop that weird and ugly macros at the top (it also has an issue with
the str4 length as it is 5 bytes long, not 4, btw):

  #define APPLETBDRM_MSG_CLEAR_DISPLAY	cpu_to_le32(0x434c5244)	/* CLRD */
  ...

(assuming we stick with __leXX for now). This will be much less confusing.

...

> >> +struct appletbdrm_msg_information {
> >> + struct appletbdrm_msg_response_header header;
> >> + u8 unk_14[12];
> >> + __le32 width;
> >> + __le32 height;
> >> + u8 bits_per_pixel;
> >> + __le32 bytes_per_row;
> >> + __le32 orientation;
> >> + __le32 bitmap_info;
> >> + __le32 pixel_format;
> >> + __le32 width_inches; /* floating point */
> >> + __le32 height_inches; /* floating point */
> >> +} __packed;
> > 
> > Haven't looked deeply into the protocol, but still makes me think that
> > the above (since it's the only __packed data type required) might be simply
> > depicted wrongly w.r.t. endianess / data types in use. It might be that
> > the data types have something combined and / or different types.
> > 
> > Do I understand correctly that the protocol was basically reverse-engineered?
> 
> Yes. Although it was reverse engineered by the person who wrote the Windows
> driver. The author has just made a Linux port.
> So, as far as how is was reverse engineered, it not really possible for me to
> explain. I don't even have any contact with the person who wrote the Windows
> driver. The only point here would be to myself RE the hardware again, which
> tbh isn't very motivating, considering that we have a working driver.

Right. I agree that is better to have something working than something
good looking, but wrong.

Can you add a summary to the commit message that since the driver was
reverse-engineered the actual data types of the protocol might be different
(including, but not limited to, endianess)?

...

> >> + /*
> >> +  * The coordinate system used by the device is different from the
> >> +  * coordinate system of the framebuffer in that the x and y axes are
> >> +  * swapped, and that the y axis is inverted; so what the device reports
> >> +  * as the height is actually the width of the framebuffer and vice
> >> +  * versa
> > 
> > Missing period.
> 
> Alright. For some reason (a mistake on my part), some dev_err_probe were also
> still left in this version.

But those are seems to me in the correct locations, no? How do we even know
the DRM device before its creation? So, dev_err_probe() calls in ->probe()
seem logical to me. Somebody from DRM should clarify this.

> >> +  */

...

> I’ll send a v5.

Please, wait a bit. it's too fast to send one version quicker than 24h...

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
> 
> ...
> 
>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>> 
>>> As commented previously this is quite strange what's going on with endianess in
>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
>>> open coded and force-cast to __le32.
>> 
>> I would assume it was also mimicked from the Windows driver, though I haven't
>> really tried exploring this there.
>> 
>> I’d rather be happy if you give me code change suggestions and let me review
>> and test them
> 
> For the starter I would do the following for all related constants and
> drop that weird and ugly macros at the top (it also has an issue with
> the str4 length as it is 5 bytes long, not 4, btw):
> 
>  #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */

Lemme test this.
>  ...
> 
> (assuming we stick with __leXX for now). This will be much less confusing.
> 
> ...
> 
>>>> +struct appletbdrm_msg_information {
>>>> + struct appletbdrm_msg_response_header header;
>>>> + u8 unk_14[12];
>>>> + __le32 width;
>>>> + __le32 height;
>>>> + u8 bits_per_pixel;
>>>> + __le32 bytes_per_row;
>>>> + __le32 orientation;
>>>> + __le32 bitmap_info;
>>>> + __le32 pixel_format;
>>>> + __le32 width_inches; /* floating point */
>>>> + __le32 height_inches; /* floating point */
>>>> +} __packed;
>>> 
>>> Haven't looked deeply into the protocol, but still makes me think that
>>> the above (since it's the only __packed data type required) might be simply
>>> depicted wrongly w.r.t. endianess / data types in use. It might be that
>>> the data types have something combined and / or different types.
>>> 
>>> Do I understand correctly that the protocol was basically reverse-engineered?
>> 
>> Yes. Although it was reverse engineered by the person who wrote the Windows
>> driver. The author has just made a Linux port.
>> So, as far as how is was reverse engineered, it not really possible for me to
>> explain. I don't even have any contact with the person who wrote the Windows
>> driver. The only point here would be to myself RE the hardware again, which
>> tbh isn't very motivating, considering that we have a working driver.
> 
> Right. I agree that is better to have something working than something
> good looking, but wrong.
> 
> Can you add a summary to the commit message that since the driver was
> reverse-engineered the actual data types of the protocol might be different
> (including, but not limited to, endianess)?

Ok

> 
> ...
> 
>>>> + /*
>>>> +  * The coordinate system used by the device is different from the
>>>> +  * coordinate system of the framebuffer in that the x and y axes are
>>>> +  * swapped, and that the y axis is inverted; so what the device reports
>>>> +  * as the height is actually the width of the framebuffer and vice
>>>> +  * versa
>>> 
>>> Missing period.
>> 
>> Alright. For some reason (a mistake on my part), some dev_err_probe were also
>> still left in this version.
> 
> But those are seems to me in the correct locations, no? How do we even know
> the DRM device before its creation? So, dev_err_probe() calls in ->probe()
> seem logical to me. Somebody from DRM should clarify this.

Thomas asked me to do this change. Maybe you didn’t see his reply.
> 
>>>> +  */
> 
> ...
> 
>> I’ll send a v5.
> 
> Please, wait a bit. it's too fast to send one version quicker than 24h...
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
> > On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
> > On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
> >>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
> >>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:

...

> >>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> >>> 
> >>> As commented previously this is quite strange what's going on with endianess in
> >>> this driver. Especially the above weirdness when get_unaligned_be32() is being
> >>> open coded and force-cast to __le32.
> >> 
> >> I would assume it was also mimicked from the Windows driver, though I haven't
> >> really tried exploring this there.
> >> 
> >> I’d rather be happy if you give me code change suggestions and let me review
> >> and test them
> > 
> > For the starter I would do the following for all related constants and
> > drop that weird and ugly macros at the top (it also has an issue with
> > the str4 length as it is 5 bytes long, not 4, btw):
> > 
> >  #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
> 
> Lemme test this.

Just in case it won't work, reverse bytes in the integer. Because I was lost in
this conversion.

> > (assuming we stick with __leXX for now). This will be much less confusing.

...

> >> Alright. For some reason (a mistake on my part), some dev_err_probe were also
> >> still left in this version.
> > 
> > But those are seems to me in the correct locations, no? How do we even know
> > the DRM device before its creation? So, dev_err_probe() calls in ->probe()
> > seem logical to me. Somebody from DRM should clarify this.
> 
> Thomas asked me to do this change. Maybe you didn’t see his reply.

I saw, maybe I took it wrong, but I really don't understand how on earth
drm_err()  or whatever can be used in real ->probe() of the physical device.

Imagine the hypotetical case

probe(strict device *dev)
{
	mydrm;
	foo;
	...
	foo = devm_gpiod_get(dev, ...);
	if (IS_ERR(foo))
		return dev_err_probe(dev, ...); // how?!
	...
	mydrm = ...DRM alloc...;
	...
}

I don't even believe it will be possible to create drm_err_probe() as it most
likely will require to have an allocation to be always the first op (that may
fail) in the ->probe() which might be not the case for some device drivers.

> >>>> +  */

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
> 
> ...
> 
>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>>>> 
>>>>> As commented previously this is quite strange what's going on with endianess in
>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
>>>>> open coded and force-cast to __le32.
>>>> 
>>>> I would assume it was also mimicked from the Windows driver, though I haven't
>>>> really tried exploring this there.
>>>> 
>>>> I’d rather be happy if you give me code change suggestions and let me review
>>>> and test them
>>> 
>>> For the starter I would do the following for all related constants and
>>> drop that weird and ugly macros at the top (it also has an issue with
>>> the str4 length as it is 5 bytes long, not 4, btw):
>>> 
>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
>> 
>> Lemme test this.
> 
> Just in case it won't work, reverse bytes in the integer. Because I was lost in
> this conversion.

It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same.
> 
>>> (assuming we stick with __leXX for now). This will be much less confusing.
> 
> ...
> 
>>>> Alright. For some reason (a mistake on my part), some dev_err_probe were also
>>>> still left in this version.
>>> 
>>> But those are seems to me in the correct locations, no? How do we even know
>>> the DRM device before its creation? So, dev_err_probe() calls in ->probe()
>>> seem logical to me. Somebody from DRM should clarify this.
>> 
>> Thomas asked me to do this change. Maybe you didn’t see his reply.
> 
> I saw, maybe I took it wrong, but I really don't understand how on earth
> drm_err()  or whatever can be used in real ->probe() of the physical device.
> 
> Imagine the hypotetical case
> 
> probe(strict device *dev)
> {
>    mydrm;
>    foo;
>    ...
>    foo = devm_gpiod_get(dev, ...);
>    if (IS_ERR(foo))
>        return dev_err_probe(dev, ...); // how?!
>    ...
>    mydrm = ...DRM alloc...;
>    ...
> }
> 
> I don't even believe it will be possible to create drm_err_probe() as it most
> likely will require to have an allocation to be always the first op (that may
> fail) in the ->probe() which might be not the case for some device drivers.
> 
>>>>>> +  */
> 
> --
> With Best Regards,
> Andy Shevchenko
> 
> 

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargaditya08@live.com> wrote:
> 
> 
> 
>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
>> 
>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
>>> 
>>> ...
>>> 
>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>>>>>> 
>>>>>>> As commented previously this is quite strange what's going on with endianess in
>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
>>>>>>> open coded and force-cast to __le32.
>>>>>> 
>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
>>>>>> really tried exploring this there.
>>>>>> 
>>>>>> I’d rather be happy if you give me code change suggestions and let me review
>>>>>> and test them
>>>>> 
>>>>> For the starter I would do the following for all related constants and
>>>>> drop that weird and ugly macros at the top (it also has an issue with
>>>>> the str4 length as it is 5 bytes long, not 4, btw):
>>>>> 
>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
>>> 
>>> Lemme test this.
>> 
>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
>> this conversion.
> 
> It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same.

And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc in reverse order, probably the reason %p4ch was chosen. And I am unable to find what macro upstream can be used.

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote:
> > On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargaditya08@live.com> wrote:
> >> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
> >> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
> >>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
> >>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:

...

> >>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> >>>>>>> 
> >>>>>>> As commented previously this is quite strange what's going on with endianess in
> >>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
> >>>>>>> open coded and force-cast to __le32.
> >>>>>> 
> >>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
> >>>>>> really tried exploring this there.
> >>>>>> 
> >>>>>> I’d rather be happy if you give me code change suggestions and let me review
> >>>>>> and test them
> >>>>> 
> >>>>> For the starter I would do the following for all related constants and
> >>>>> drop that weird and ugly macros at the top (it also has an issue with
> >>>>> the str4 length as it is 5 bytes long, not 4, btw):
> >>>>> 
> >>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
> >>> 
> >>> Lemme test this.
> >> 
> >> Just in case it won't work, reverse bytes in the integer. Because I was lost in
> >> this conversion.
> > 
> > It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same.
> 
> And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc
> in reverse order, probably the reason %p4ch was chosen. And I am unable to
> find what macro upstream can be used.

%.4s should work as it technically not DRM 4cc, but specifics of the protocol
(that reminds me about ACPI that uses 4cc a lot).

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 9:08 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote:
>>> On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargaditya08@live.com> wrote:
>>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
>>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
>>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
>>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
>> 
>> ...
>> 
>>>>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>>>>>>>>> 
>>>>>>>>>> As commented previously this is quite strange what's going on with endianess in
>>>>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
>>>>>>>>>> open coded and force-cast to __le32.
>>>>>>>>> 
>>>>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
>>>>>>>>> really tried exploring this there.
>>>>>>>>> 
>>>>>>>>> I’d rather be happy if you give me code change suggestions and let me review
>>>>>>>>> and test them
>>>>>>>> 
>>>>>>>> For the starter I would do the following for all related constants and
>>>>>>>> drop that weird and ugly macros at the top (it also has an issue with
>>>>>>>> the str4 length as it is 5 bytes long, not 4, btw):
>>>>>>>> 
>>>>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
>>>>>> 
>>>>>> Lemme test this.
>>>>> 
>>>>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
>>>>> this conversion.
>>> 
>>> It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same.
>> 
>> And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc
>> in reverse order, probably the reason %p4ch was chosen. And I am unable to
>> find what macro upstream can be used.
> 
> %.4s should work as it technically not DRM 4cc, but specifics of the protocol
> (that reminds me about ACPI that uses 4cc a lot).

I still get reverse order in that.
> 
> --
> With Best Regards,
> Andy Shevchenko
> 
> 

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 03:40:29PM +0000, Aditya Garg wrote:
> > On 24 Feb 2025, at 9:08 PM, andriy.shevchenko@linux.intel.com wrote:
> > On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote:
> >>> On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargaditya08@live.com> wrote:
> >>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
> >>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
> >>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:

...

> >>>>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> >>>>>>>>>> 
> >>>>>>>>>> As commented previously this is quite strange what's going on with endianess in
> >>>>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
> >>>>>>>>>> open coded and force-cast to __le32.
> >>>>>>>>> 
> >>>>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
> >>>>>>>>> really tried exploring this there.
> >>>>>>>>> 
> >>>>>>>>> I’d rather be happy if you give me code change suggestions and let me review
> >>>>>>>>> and test them
> >>>>>>>> 
> >>>>>>>> For the starter I would do the following for all related constants and
> >>>>>>>> drop that weird and ugly macros at the top (it also has an issue with
> >>>>>>>> the str4 length as it is 5 bytes long, not 4, btw):
> >>>>>>>> 
> >>>>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
> >>>>>> 
> >>>>>> Lemme test this.
> >>>>> 
> >>>>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
> >>>>> this conversion.
> >>> 
> >>> It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same.
> >> 
> >> And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc
> >> in reverse order, probably the reason %p4ch was chosen. And I am unable to
> >> find what macro upstream can be used.
> > 
> > %.4s should work as it technically not DRM 4cc, but specifics of the protocol
> > (that reminds me about ACPI that uses 4cc a lot).
> 
> I still get reverse order in that.

Ah, right, it will give you the first letter as LSB, indeed. At the end of the
day if it's so important, there are ways how to solve that without using %p4cc.
But if others (and esp. PRINTK maintainers) want to have / don't object having
that extension, why not?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 9:23 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 03:40:29PM +0000, Aditya Garg wrote:
>>>> On 24 Feb 2025, at 9:08 PM, andriy.shevchenko@linux.intel.com wrote:
>>> On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote:
>>>>> On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargaditya08@live.com> wrote:
>>>>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
>>>>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
>>>>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
> 
> ...
> 
>>>>>>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>>>>>>>>>>> 
>>>>>>>>>>>> As commented previously this is quite strange what's going on with endianess in
>>>>>>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
>>>>>>>>>>>> open coded and force-cast to __le32.
>>>>>>>>>>> 
>>>>>>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
>>>>>>>>>>> really tried exploring this there.
>>>>>>>>>>> 
>>>>>>>>>>> I’d rather be happy if you give me code change suggestions and let me review
>>>>>>>>>>> and test them
>>>>>>>>>> 
>>>>>>>>>> For the starter I would do the following for all related constants and
>>>>>>>>>> drop that weird and ugly macros at the top (it also has an issue with
>>>>>>>>>> the str4 length as it is 5 bytes long, not 4, btw):
>>>>>>>>>> 
>>>>>>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
>>>>>>>> 
>>>>>>>> Lemme test this.
>>>>>>> 
>>>>>>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
>>>>>>> this conversion.
>>>>> 
>>>>> It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same.
>>>> 
>>>> And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc
>>>> in reverse order, probably the reason %p4ch was chosen. And I am unable to
>>>> find what macro upstream can be used.
>>> 
>>> %.4s should work as it technically not DRM 4cc, but specifics of the protocol
>>> (that reminds me about ACPI that uses 4cc a lot).
>> 
>> I still get reverse order in that.
> 
> Ah, right, it will give you the first letter as LSB, indeed. At the end of the
> day if it's so important, there are ways how to solve that without using %p4cc.
> But if others (and esp. PRINTK maintainers) want to have / don't object having
> that extension, why not?

Right, but what to do about the case of little endian and host endian? I remember the statement "for the sake of completeness" for them. Do you think just host endian and reverse endian should be just fine? Or you got any "no sparse warning" way to get it done? The macros to convert to le32/be32 expect a u32 value, but in those cases we actually are passing a le32/be32 value.

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 9:26 PM, Aditya Garg <gargaditya08@live.com> wrote:
> 
> 
> 
>> On 24 Feb 2025, at 9:23 PM, andriy.shevchenko@linux.intel.com wrote:
>> 
>> On Mon, Feb 24, 2025 at 03:40:29PM +0000, Aditya Garg wrote:
>>>>> On 24 Feb 2025, at 9:08 PM, andriy.shevchenko@linux.intel.com wrote:
>>>> On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote:
>>>>>> On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargaditya08@live.com> wrote:
>>>>>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
>>>>>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
>>>>>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>>>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
>>> 
>>> ...
>>> 
>>>>>>>>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>>>>>>>>>>>>> 
>>>>>>>>>>>>>> As commented previously this is quite strange what's going on with endianess in
>>>>>>>>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
>>>>>>>>>>>>>> open coded and force-cast to __le32.
>>>>>>>>>>>>> 
>>>>>>>>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
>>>>>>>>>>>>> really tried exploring this there.
>>>>>>>>>>>>> 
>>>>>>>>>>>>> I’d rather be happy if you give me code change suggestions and let me review
>>>>>>>>>>>>> and test them
>>>>>>>>>>>> 
>>>>>>>>>>>> For the starter I would do the following for all related constants and
>>>>>>>>>>>> drop that weird and ugly macros at the top (it also has an issue with
>>>>>>>>>>>> the str4 length as it is 5 bytes long, not 4, btw):
>>>>>>>>>>>> 
>>>>>>>>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
>>>>>>>>>> 
>>>>>>>>>> Lemme test this.
>>>>>>>>> 
>>>>>>>>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
>>>>>>>>> this conversion.
>>>>>>> 
>>>>>>> It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same.
>>>>>> 
>>>>>> And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc
>>>>>> in reverse order, probably the reason %p4ch was chosen. And I am unable to
>>>>>> find what macro upstream can be used.
>>>>> 
>>>>> %.4s should work as it technically not DRM 4cc, but specifics of the protocol
>>>>> (that reminds me about ACPI that uses 4cc a lot).
>>> 
>>> I still get reverse order in that.
>> 
>> Ah, right, it will give you the first letter as LSB, indeed. At the end of the
>> day if it's so important, there are ways how to solve that without using %p4cc.
>> But if others (and esp. PRINTK maintainers) want to have / don't object having
>> that extension, why not?
> 
> Right, but what to do about the case of little endian and host endian? I remember the statement "for the sake of completeness" for them. Do you think just host endian and reverse endian should be just fine? Or you got any "no sparse warning" way to get it done? The macros to convert to le32/be32 expect a u32 value, but in those cases we actually are passing a le32/be32 value.

We can convert the __le32 to be printed by %p4cc to __be32.

__be32 expected_response_be = cpu_to_be32(le32_to_cpu(expected_response));

That's seems to be the best possible option to fix this revert.

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 03:56:36PM +0000, Aditya Garg wrote:
> > On 24 Feb 2025, at 9:23 PM, andriy.shevchenko@linux.intel.com wrote:
> > On Mon, Feb 24, 2025 at 03:40:29PM +0000, Aditya Garg wrote:
> >>>> On 24 Feb 2025, at 9:08 PM, andriy.shevchenko@linux.intel.com wrote:
> >>> On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote:
> >>>>> On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargaditya08@live.com> wrote:
> >>>>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
> >>>>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
> >>>>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>>>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:

...

> >>>>>>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> >>>>>>>>>>>> 
> >>>>>>>>>>>> As commented previously this is quite strange what's going on with endianess in
> >>>>>>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
> >>>>>>>>>>>> open coded and force-cast to __le32.
> >>>>>>>>>>> 
> >>>>>>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
> >>>>>>>>>>> really tried exploring this there.
> >>>>>>>>>>> 
> >>>>>>>>>>> I’d rather be happy if you give me code change suggestions and let me review
> >>>>>>>>>>> and test them
> >>>>>>>>>> 
> >>>>>>>>>> For the starter I would do the following for all related constants and
> >>>>>>>>>> drop that weird and ugly macros at the top (it also has an issue with
> >>>>>>>>>> the str4 length as it is 5 bytes long, not 4, btw):
> >>>>>>>>>> 
> >>>>>>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
> >>>>>>>> 
> >>>>>>>> Lemme test this.
> >>>>>>> 
> >>>>>>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
> >>>>>>> this conversion.
> >>>>> 
> >>>>> It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same.
> >>>> 
> >>>> And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc
> >>>> in reverse order, probably the reason %p4ch was chosen. And I am unable to
> >>>> find what macro upstream can be used.
> >>> 
> >>> %.4s should work as it technically not DRM 4cc, but specifics of the protocol
> >>> (that reminds me about ACPI that uses 4cc a lot).
> >> 
> >> I still get reverse order in that.
> > 
> > Ah, right, it will give you the first letter as LSB, indeed. At the end of the
> > day if it's so important, there are ways how to solve that without using %p4cc.
> > But if others (and esp. PRINTK maintainers) want to have / don't object having
> > that extension, why not?
> 
> Right, but what to do about the case of little endian and host endian? I
> remember the statement "for the sake of completeness" for them. Do you think
> just host endian and reverse endian should be just fine? Or you got any "no
> sparse warning" way to get it done? The macros to convert to le32/be32 expect
> a u32 value, but in those cases we actually are passing a le32/be32 value.

For now I think we better save the energy and wait for PRINTK people to tell
if they are okay in general. Otherwise it makes no sense to develop and review
something that will go to the trash bin.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 9:45 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 03:56:36PM +0000, Aditya Garg wrote:
>>>> On 24 Feb 2025, at 9:23 PM, andriy.shevchenko@linux.intel.com wrote:
>>> On Mon, Feb 24, 2025 at 03:40:29PM +0000, Aditya Garg wrote:
>>>>>> On 24 Feb 2025, at 9:08 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>> On Mon, Feb 24, 2025 at 03:32:56PM +0000, Aditya Garg wrote:
>>>>>>> On 24 Feb 2025, at 8:50 PM, Aditya Garg <gargaditya08@live.com> wrote:
>>>>>>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
>>>>>>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
>>>>>>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>>>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
> 
> ...
> 
>>>>>>>>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>>>>>>>>>>>>> 
>>>>>>>>>>>>>> As commented previously this is quite strange what's going on with endianess in
>>>>>>>>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
>>>>>>>>>>>>>> open coded and force-cast to __le32.
>>>>>>>>>>>>> 
>>>>>>>>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
>>>>>>>>>>>>> really tried exploring this there.
>>>>>>>>>>>>> 
>>>>>>>>>>>>> I’d rather be happy if you give me code change suggestions and let me review
>>>>>>>>>>>>> and test them
>>>>>>>>>>>> 
>>>>>>>>>>>> For the starter I would do the following for all related constants and
>>>>>>>>>>>> drop that weird and ugly macros at the top (it also has an issue with
>>>>>>>>>>>> the str4 length as it is 5 bytes long, not 4, btw):
>>>>>>>>>>>> 
>>>>>>>>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
>>>>>>>>>> 
>>>>>>>>>> Lemme test this.
>>>>>>>>> 
>>>>>>>>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
>>>>>>>>> this conversion.
>>>>>>> 
>>>>>>> It works. What I understand is that you used the macro to get the final hex and converted it into little endian, which on the x86 macs would technically remain the same.
>>>>>> 
>>>>>> And now that I oberved again, %p4cc is actually printing these CLRD, REDY etc
>>>>>> in reverse order, probably the reason %p4ch was chosen. And I am unable to
>>>>>> find what macro upstream can be used.
>>>>> 
>>>>> %.4s should work as it technically not DRM 4cc, but specifics of the protocol
>>>>> (that reminds me about ACPI that uses 4cc a lot).
>>>> 
>>>> I still get reverse order in that.
>>> 
>>> Ah, right, it will give you the first letter as LSB, indeed. At the end of the
>>> day if it's so important, there are ways how to solve that without using %p4cc.
>>> But if others (and esp. PRINTK maintainers) want to have / don't object having
>>> that extension, why not?
>> 
>> Right, but what to do about the case of little endian and host endian? I
>> remember the statement "for the sake of completeness" for them. Do you think
>> just host endian and reverse endian should be just fine? Or you got any "no
>> sparse warning" way to get it done? The macros to convert to le32/be32 expect
>> a u32 value, but in those cases we actually are passing a le32/be32 value.
> 
> For now I think we better save the energy and wait for PRINTK people to tell
> if they are okay in general. Otherwise it makes no sense to develop and review
> something that will go to the trash bin.
> 

I'd rather keep %p4cc here for now. I don't know in detail about FOURCC tbh, so probably just let Asahi Linux manage that part if more changes are needed. In case we get better printk formats, a subsequent patch can be sent later. %p4cc still works just fine.

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 03:20:13PM +0000, Aditya Garg wrote:
> > On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
> > On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
> >>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
> >>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
> >>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:

...

> >>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> >>>>> 
> >>>>> As commented previously this is quite strange what's going on with endianess in
> >>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
> >>>>> open coded and force-cast to __le32.
> >>>> 
> >>>> I would assume it was also mimicked from the Windows driver, though I haven't
> >>>> really tried exploring this there.
> >>>> 
> >>>> I’d rather be happy if you give me code change suggestions and let me review
> >>>> and test them
> >>> 
> >>> For the starter I would do the following for all related constants and
> >>> drop that weird and ugly macros at the top (it also has an issue with
> >>> the str4 length as it is 5 bytes long, not 4, btw):
> >>> 
> >>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
> >> 
> >> Lemme test this.
> > 
> > Just in case it won't work, reverse bytes in the integer. Because I was lost in
> > this conversion.
> 
> It works. What I understand is that you used the macro to get the final hex
> and converted it into little endian, which on the x86 macs would technically
> remain the same.

Right, the problem is the macro itself which does really weird things altogether.
Using integer + comment much clearer in my opinion.

> >>> (assuming we stick with __leXX for now). This will be much less confusing.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 9:07 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 03:20:13PM +0000, Aditya Garg wrote:
>>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
> 
> ...
> 
>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>>>>>> 
>>>>>>> As commented previously this is quite strange what's going on with endianess in
>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
>>>>>>> open coded and force-cast to __le32.
>>>>>> 
>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
>>>>>> really tried exploring this there.
>>>>>> 
>>>>>> I’d rather be happy if you give me code change suggestions and let me review
>>>>>> and test them
>>>>> 
>>>>> For the starter I would do the following for all related constants and
>>>>> drop that weird and ugly macros at the top (it also has an issue with
>>>>> the str4 length as it is 5 bytes long, not 4, btw):
>>>>> 
>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
>>>> 
>>>> Lemme test this.
>>> 
>>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
>>> this conversion.
>> 
>> It works. What I understand is that you used the macro to get the final hex
>> and converted it into little endian, which on the x86 macs would technically
>> remain the same.
> 

The Macro is just converting the letters into their hex form, but simply calculating them and putting the letters in comments is equally good.

> Right, the problem is the macro itself which does really weird things altogether.
> Using integer + comment much clearer in my opinion.
> 
>>>>> (assuming we stick with __leXX for now). This will be much less confusing.
> 
> --
> With Best Regards,
> Andy Shevchenko
> 
> 

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 03:39:56PM +0000, Aditya Garg wrote:
> > On 24 Feb 2025, at 9:07 PM, andriy.shevchenko@linux.intel.com wrote:
> > On Mon, Feb 24, 2025 at 03:20:13PM +0000, Aditya Garg wrote:
> >>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
> >>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
> >>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
> >>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:

...

> >>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> >>>>>>> 
> >>>>>>> As commented previously this is quite strange what's going on with endianess in
> >>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
> >>>>>>> open coded and force-cast to __le32.
> >>>>>> 
> >>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
> >>>>>> really tried exploring this there.
> >>>>>> 
> >>>>>> I’d rather be happy if you give me code change suggestions and let me review
> >>>>>> and test them
> >>>>> 
> >>>>> For the starter I would do the following for all related constants and
> >>>>> drop that weird and ugly macros at the top (it also has an issue with
> >>>>> the str4 length as it is 5 bytes long, not 4, btw):
> >>>>> 
> >>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
> >>>> 
> >>>> Lemme test this.
> >>> 
> >>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
> >>> this conversion.
> >> 
> >> It works. What I understand is that you used the macro to get the final hex
> >> and converted it into little endian, which on the x86 macs would technically
> >> remain the same.
> 
> The Macro is just converting the letters into their hex form, but simply
> calculating them and putting the letters in comments is equally good.

Again, it does it in most confusing and weird way. Just kill it.

> > Right, the problem is the macro itself which does really weird things altogether.
> > Using integer + comment much clearer in my opinion.
> > 
> >>>>> (assuming we stick with __leXX for now). This will be much less confusing.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 9:19 PM, andriy.shevchenko@linux.intel.com wrote:
> 
> On Mon, Feb 24, 2025 at 03:39:56PM +0000, Aditya Garg wrote:
>>>> On 24 Feb 2025, at 9:07 PM, andriy.shevchenko@linux.intel.com wrote:
>>> On Mon, Feb 24, 2025 at 03:20:13PM +0000, Aditya Garg wrote:
>>>>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
>>>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
>>>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
>>>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:
> 
> ...
> 
>>>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>>>>>>>> 
>>>>>>>>> As commented previously this is quite strange what's going on with endianess in
>>>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
>>>>>>>>> open coded and force-cast to __le32.
>>>>>>>> 
>>>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
>>>>>>>> really tried exploring this there.
>>>>>>>> 
>>>>>>>> I’d rather be happy if you give me code change suggestions and let me review
>>>>>>>> and test them
>>>>>>> 
>>>>>>> For the starter I would do the following for all related constants and
>>>>>>> drop that weird and ugly macros at the top (it also has an issue with
>>>>>>> the str4 length as it is 5 bytes long, not 4, btw):
>>>>>>> 
>>>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
>>>>>> 
>>>>>> Lemme test this.
>>>>> 
>>>>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
>>>>> this conversion.
>>>> 
>>>> It works. What I understand is that you used the macro to get the final hex
>>>> and converted it into little endian, which on the x86 macs would technically
>>>> remain the same.
>> 
>> The Macro is just converting the letters into their hex form, but simply
>> calculating them and putting the letters in comments is equally good.
> 
> Again, it does it in most confusing and weird way. Just kill it.

#define APPLETBDRM_PIXEL_FORMAT		cpu_to_le32(0x52474241) /* RGBA, the actual format is BGR888 */
#define APPLETBDRM_BITS_PER_PIXEL	24

#define APPLETBDRM_MSG_CLEAR_DISPLAY	cpu_to_le32(0x434c5244) /* CLRD */
#define APPLETBDRM_MSG_GET_INFORMATION	cpu_to_le32(0x47494e46) /* GINF */
#define APPLETBDRM_MSG_UPDATE_COMPLETE	cpu_to_le32(0x5544434c) /* UDCL */
#define APPLETBDRM_MSG_SIGNAL_READINESS	cpu_to_le32(0x52454459) /* REDY */

This should be good.

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Mon, Feb 24, 2025 at 03:52:03PM +0000, Aditya Garg wrote:
> > On 24 Feb 2025, at 9:19 PM, andriy.shevchenko@linux.intel.com wrote:
> > On Mon, Feb 24, 2025 at 03:39:56PM +0000, Aditya Garg wrote:
> >>>> On 24 Feb 2025, at 9:07 PM, andriy.shevchenko@linux.intel.com wrote:
> >>> On Mon, Feb 24, 2025 at 03:20:13PM +0000, Aditya Garg wrote:
> >>>>>> On 24 Feb 2025, at 8:41 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>> On Mon, Feb 24, 2025 at 03:03:40PM +0000, Aditya Garg wrote:
> >>>>>>>> On 24 Feb 2025, at 8:27 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>>>> On Mon, Feb 24, 2025 at 02:32:37PM +0000, Aditya Garg wrote:
> >>>>>>>>> On 24 Feb 2025, at 7:30 PM, andriy.shevchenko@linux.intel.com wrote:
> >>>>>>>>> On Mon, Feb 24, 2025 at 01:40:20PM +0000, Aditya Garg wrote:

...

> >>>>>>>>>> +#define __APPLETBDRM_MSG_STR4(str4) ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> >>>>>>>>> 
> >>>>>>>>> As commented previously this is quite strange what's going on with endianess in
> >>>>>>>>> this driver. Especially the above weirdness when get_unaligned_be32() is being
> >>>>>>>>> open coded and force-cast to __le32.
> >>>>>>>> 
> >>>>>>>> I would assume it was also mimicked from the Windows driver, though I haven't
> >>>>>>>> really tried exploring this there.
> >>>>>>>> 
> >>>>>>>> I’d rather be happy if you give me code change suggestions and let me review
> >>>>>>>> and test them
> >>>>>>> 
> >>>>>>> For the starter I would do the following for all related constants and
> >>>>>>> drop that weird and ugly macros at the top (it also has an issue with
> >>>>>>> the str4 length as it is 5 bytes long, not 4, btw):
> >>>>>>> 
> >>>>>>> #define APPLETBDRM_MSG_CLEAR_DISPLAY cpu_to_le32(0x434c5244) /* CLRD */
> >>>>>> 
> >>>>>> Lemme test this.
> >>>>> 
> >>>>> Just in case it won't work, reverse bytes in the integer. Because I was lost in
> >>>>> this conversion.
> >>>> 
> >>>> It works. What I understand is that you used the macro to get the final hex
> >>>> and converted it into little endian, which on the x86 macs would technically
> >>>> remain the same.
> >> 
> >> The Macro is just converting the letters into their hex form, but simply
> >> calculating them and putting the letters in comments is equally good.
> > 
> > Again, it does it in most confusing and weird way. Just kill it.
> 
> #define APPLETBDRM_PIXEL_FORMAT		cpu_to_le32(0x52474241) /* RGBA, the actual format is BGR888 */
> #define APPLETBDRM_BITS_PER_PIXEL	24
> 
> #define APPLETBDRM_MSG_CLEAR_DISPLAY	cpu_to_le32(0x434c5244) /* CLRD */
> #define APPLETBDRM_MSG_GET_INFORMATION	cpu_to_le32(0x47494e46) /* GINF */
> #define APPLETBDRM_MSG_UPDATE_COMPLETE	cpu_to_le32(0x5544434c) /* UDCL */
> #define APPLETBDRM_MSG_SIGNAL_READINESS	cpu_to_le32(0x52454459) /* REDY */
> 
> This should be good.

Yep, way better than the original code!

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 24 Feb 2025, at 7:10 PM, Aditya Garg <gargaditya08@live.com> wrote:
> 
> From: Kerem Karabay <kekrby@gmail.com>
> 
> The Touch Bars found on x86 Macs support two USB configurations: one
> where the device presents itself as a HID keyboard and can display
> predefined sets of keys, and one where the operating system has full
> control over what is displayed.
> 
> This commit adds support for the display functionality of the second
> configuration. Functionality for the first configuration has been
> merged in the HID tree.
> 
> Note that this driver has only been tested on T2 Macs, and only includes
> the USB device ID for these devices. Testing on T1 Macs would be
> appreciated.
> 
> Credit goes to Ben (Bingxing) Wang on GitHub for reverse engineering
> most of the protocol.
> 
> Also, as requested by Andy, I would like to clarify the use of __packed
> structs in this driver:
> 
> - All the packed structs are aligned except for appletbdrm_msg_information.
> - We have to pack appletbdrm_msg_information since it is requirement of
>  the protocol.
> - We compared binaries compiled by keeping the rest structs __packed and
>  not __packed using bloat-o-meter, and __packed was not affecting code
>  generation.
> - To maintain consistency, rest structs have been kept __packed.
> 
> Link: https://github.com/imbushuo/DFRDisplayKm
> Signed-off-by: Kerem Karabay <kekrby@gmail.com>
> Co-developed-by: Atharva Tiwari <evepolonium@gmail.com>
> Signed-off-by: Atharva Tiwari <evepolonium@gmail.com>
> Co-developed-by: Aditya Garg <gargaditya08@live.com>
> Signed-off-by: Aditya Garg <gargaditya08@live.com>
> Signed-off-by: Aun-Ali Zaidi <admin@kodeit.net>
> ---
> v2 ->
> - Add the driver to MAINTAINERS.
> - Allocate memory for request and response in plane's atomic-check helper
> - Void the use of drm_fb_blit()
> - Implement atomic_disable
> - Make PRIME work
> - Remove the date field from struct drm_driver
> - intersect damage with dst_clip
> - Register DRM device in appletbdrm_probe
> - Clear the display as the final call in probe
> - Select hid_multitouch as well in kconfig
> 
> v3 ->
> - Change commit message to credit Ben (Bingxing) Wang
> 
> v4 ->
> - Use "Link:" in commit message
> - Specify why __packed has been used in commit message
> - Use %p4cc instead of %p4ch for errors
> - Add myself to Maintainers
> - Remove #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> - Add missing header files
> - Use return 0; instead of return ret; in static int appletbdrm_send_request
> - Better errno types used in appletbdrm_read_response
> - Use BITS_TO_BYTES() to convert APPLETBDRM_BITS_PER_PIXEL to bytes
> - Remove redundant else in plane_helper_atomic_check
> - Remove unnecessary use of 0xff in request->msg_id = timestamp & 0xff;
> - Remove duplicated struct device in struct appletbdrm_device
> - clear frames_size and request_size as well in primary_plane_helper_atomic_update
> - Allocate using kzalloc instead of kmemdup
> - Use drm_err() instead of dev_err_probe()
> - Avoid clearing drm->mode_config.min_width and height to 0
> - Use put_device() to release the DMA device in appletbdrm_disconnect
> 
> MAINTAINERS                       |   8 +
> drivers/gpu/drm/tiny/Kconfig      |  14 +
> drivers/gpu/drm/tiny/Makefile     |   1 +
> drivers/gpu/drm/tiny/appletbdrm.c | 835 ++++++++++++++++++++++++++++++
> 4 files changed, 858 insertions(+)
> create mode 100644 drivers/gpu/drm/tiny/appletbdrm.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index efee40ea5..f7c97eb24 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7148,6 +7148,14 @@ S:    Supported
> T:    git https://gitlab.freedesktop.org/drm/misc/kernel.git
> F:    drivers/gpu/drm/sun4i/sun8i*
> 
> +DRM DRIVER FOR APPLE TOUCH BARS
> +M:    Aun-Ali Zaidi <admin@kodeit.net>
> +M:    Aditya Garg <gargaditya08@live.com>
> +L:    dri-devel@lists.freedesktop.org
> +S:    Maintained
> +T:    git https://gitlab.freedesktop.org/drm/misc/kernel.git
> +F:    drivers/gpu/drm/tiny/appletbdrm.c
> +
> DRM DRIVER FOR ARM PL111 CLCD
> M:    Linus Walleij <linus.walleij@linaro.org>
> S:    Maintained
> diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
> index 94cbdb133..25471791c 100644
> --- a/drivers/gpu/drm/tiny/Kconfig
> +++ b/drivers/gpu/drm/tiny/Kconfig
> @@ -1,5 +1,19 @@
> # SPDX-License-Identifier: GPL-2.0-only
> 
> +config DRM_APPLETBDRM
> +    tristate "DRM support for Apple Touch Bars"
> +    depends on DRM && USB && MMU
> +    select DRM_GEM_SHMEM_HELPER
> +    select DRM_KMS_HELPER
> +    select HID_APPLETB_BL

Btw I have a doubt regarding this dependency. While hid-appletb-bl has made into the linux-next tree, it has still not been merged into Linus' tree, and neither the drm tree I assume. It potentially could cause issues?

> +    select HID_MULTITOUCH
> +    help
> +      Say Y here if you want support for the display of Touch Bars on x86
> +      MacBook Pros.
> +
> +      To compile this driver as a module, choose M here: the
> +      module will be called appletbdrm.
> +

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Thomas Zimmermann]

Hi

Am 24.02.25 um 17:58 schrieb Aditya Garg:
[...]
>>
>> +config DRM_APPLETBDRM
>> +    tristate "DRM support for Apple Touch Bars"
>> +    depends on DRM && USB && MMU
>> +    select DRM_GEM_SHMEM_HELPER
>> +    select DRM_KMS_HELPER
>> +    select HID_APPLETB_BL
> Btw I have a doubt regarding this dependency. While hid-appletb-bl has made into the linux-next tree, it has still not been merged into Linus' tree, and neither the drm tree I assume. It potentially could cause issues?

Yes. We cannot merge this driver until we have this symbol in our tree. 
But that will happen sooner or later.

More problematic is that your driver selects HID_APPLETB_BL. From what 
I've seen, this symbol is user configurable, so the driver shouldn't 
select it. You need to use 'depends on' instead of 'select' here.

Best regards
Thomas

>
>> +    select HID_MULTITOUCH
>> +    help
>> +      Say Y here if you want support for the display of Touch Bars on x86
>> +      MacBook Pros.
>> +
>> +      To compile this driver as a module, choose M here: the
>> +      module will be called appletbdrm.
>> +

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 25 Feb 2025, at 1:27 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
> 
> Hi
> 
> Am 24.02.25 um 17:58 schrieb Aditya Garg:
> [...]
>>> 
>>> +config DRM_APPLETBDRM
>>> +    tristate "DRM support for Apple Touch Bars"
>>> +    depends on DRM && USB && MMU
>>> +    select DRM_GEM_SHMEM_HELPER
>>> +    select DRM_KMS_HELPER
>>> +    select HID_APPLETB_BL
>> Btw I have a doubt regarding this dependency. While hid-appletb-bl has made into the linux-next tree, it has still not been merged into Linus' tree, and neither the drm tree I assume. It potentially could cause issues?
> 
> Yes. We cannot merge this driver until we have this symbol in our tree. But that will happen sooner or later.
> 
> More problematic is that your driver selects HID_APPLETB_BL. From what I've seen, this symbol is user configurable, so the driver shouldn't select it. You need to use 'depends on' instead of 'select' here.

I assume we need the same for HID_MULTITOUCH as well, since it's needed for the touch feedback.
> 
> Best regards
> Thomas
> 
>> 
>>> +    select HID_MULTITOUCH
>>> +    help
>>> +      Say Y here if you want support for the display of Touch Bars on x86
>>> +      MacBook Pros.
>>> +
>>> +      To compile this driver as a module, choose M here: the
>>> +      module will be called appletbdrm.
>>> +
> 
> --
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Frankenstrasse 146, 90461 Nuernberg, Germany
> GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
> HRB 36809 (AG Nuernberg)
> 

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Thomas Zimmermann]

Hi

Am 25.02.25 um 09:02 schrieb Aditya Garg:
>
>> On 25 Feb 2025, at 1:27 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>>
>> Hi
>>
>> Am 24.02.25 um 17:58 schrieb Aditya Garg:
>> [...]
>>>> +config DRM_APPLETBDRM
>>>> +    tristate "DRM support for Apple Touch Bars"
>>>> +    depends on DRM && USB && MMU
>>>> +    select DRM_GEM_SHMEM_HELPER
>>>> +    select DRM_KMS_HELPER
>>>> +    select HID_APPLETB_BL
>>> Btw I have a doubt regarding this dependency. While hid-appletb-bl has made into the linux-next tree, it has still not been merged into Linus' tree, and neither the drm tree I assume. It potentially could cause issues?
>> Yes. We cannot merge this driver until we have this symbol in our tree. But that will happen sooner or later.
>>
>> More problematic is that your driver selects HID_APPLETB_BL. From what I've seen, this symbol is user configurable, so the driver shouldn't select it. You need to use 'depends on' instead of 'select' here.
> I assume we need the same for HID_MULTITOUCH as well, since it's needed for the touch feedback.

Indeed. Same goes for HID_MULTITOUCH.

Best regards
Thomas

>> Best regards
>> Thomas
>>
>>>> +    select HID_MULTITOUCH
>>>> +    help
>>>> +      Say Y here if you want support for the display of Touch Bars on x86
>>>> +      MacBook Pros.
>>>> +
>>>> +      To compile this driver as a module, choose M here: the
>>>> +      module will be called appletbdrm.
>>>> +
>> --
>> --
>> Thomas Zimmermann
>> Graphics Driver Developer
>> SUSE Software Solutions Germany GmbH
>> Frankenstrasse 146, 90461 Nuernberg, Germany
>> GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
>> HRB 36809 (AG Nuernberg)
>>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 25 Feb 2025, at 1:27 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
> 
> Hi
> 
> Am 24.02.25 um 17:58 schrieb Aditya Garg:
> [...]
>>> 
>>> +config DRM_APPLETBDRM
>>> +    tristate "DRM support for Apple Touch Bars"
>>> +    depends on DRM && USB && MMU
>>> +    select DRM_GEM_SHMEM_HELPER
>>> +    select DRM_KMS_HELPER
>>> +    select HID_APPLETB_BL
>> Btw I have a doubt regarding this dependency. While hid-appletb-bl has made into the linux-next tree, it has still not been merged into Linus' tree, and neither the drm tree I assume. It potentially could cause issues?
> 
> Yes. We cannot merge this driver until we have this symbol in our tree. But that will happen sooner or later.
> 
> More problematic is that your driver selects HID_APPLETB_BL. From what I've seen, this symbol is user configurable, so the driver shouldn't select it. You need to use 'depends on' instead of 'select' here.

Looking at this again, maybe it should be selected. If you see the kernel config of TINYDRM_HX8357D, which is also in drm/tiny, it is selecting BACKLIGHT_CLASS_DEVICE.
> 
> Best regards
> Thomas
> 
>> 
>>> +    select HID_MULTITOUCH
>>> +    help
>>> +      Say Y here if you want support for the display of Touch Bars on x86
>>> +      MacBook Pros.
>>> +
>>> +      To compile this driver as a module, choose M here: the
>>> +      module will be called appletbdrm.
>>> +
> 
> --
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Frankenstrasse 146, 90461 Nuernberg, Germany
> GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
> HRB 36809 (AG Nuernberg)
> 

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 25 Feb 2025, at 2:34 PM, Aditya Garg <gargaditya08@live.com> wrote:
> 
> 
> 
>> On 25 Feb 2025, at 1:27 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>> 
>> Hi
>> 
>> Am 24.02.25 um 17:58 schrieb Aditya Garg:
>> [...]
>>>> 
>>>> +config DRM_APPLETBDRM
>>>> +    tristate "DRM support for Apple Touch Bars"
>>>> +    depends on DRM && USB && MMU
>>>> +    select DRM_GEM_SHMEM_HELPER
>>>> +    select DRM_KMS_HELPER
>>>> +    select HID_APPLETB_BL
>>> Btw I have a doubt regarding this dependency. While hid-appletb-bl has made into the linux-next tree, it has still not been merged into Linus' tree, and neither the drm tree I assume. It potentially could cause issues?
>> 
>> Yes. We cannot merge this driver until we have this symbol in our tree. But that will happen sooner or later.
>> 
>> More problematic is that your driver selects HID_APPLETB_BL. From what I've seen, this symbol is user configurable, so the driver shouldn't select it. You need to use 'depends on' instead of 'select' here.
> 
> Looking at this again, maybe it should be selected. If you see the kernel config of TINYDRM_HX8357D, which is also in drm/tiny, it is selecting BACKLIGHT_CLASS_DEVICE.

To make things more clear, 

1. hid-appletb-bl is for the backlight of the touchbar. The DRM code remains separate.
2. hid-multitouch is to make the touchbar a touch screen. You can still use the driver without the touch functionality.

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Thomas Zimmermann]

Hi

Am 25.02.25 um 10:07 schrieb Aditya Garg:
>
>> On 25 Feb 2025, at 2:34 PM, Aditya Garg <gargaditya08@live.com> wrote:
>>
>> 
>>
>>> On 25 Feb 2025, at 1:27 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>>>
>>> Hi
>>>
>>> Am 24.02.25 um 17:58 schrieb Aditya Garg:
>>> [...]
>>>>> +config DRM_APPLETBDRM
>>>>> +    tristate "DRM support for Apple Touch Bars"
>>>>> +    depends on DRM && USB && MMU
>>>>> +    select DRM_GEM_SHMEM_HELPER
>>>>> +    select DRM_KMS_HELPER
>>>>> +    select HID_APPLETB_BL
>>>> Btw I have a doubt regarding this dependency. While hid-appletb-bl has made into the linux-next tree, it has still not been merged into Linus' tree, and neither the drm tree I assume. It potentially could cause issues?
>>> Yes. We cannot merge this driver until we have this symbol in our tree. But that will happen sooner or later.
>>>
>>> More problematic is that your driver selects HID_APPLETB_BL. From what I've seen, this symbol is user configurable, so the driver shouldn't select it. You need to use 'depends on' instead of 'select' here.
>> Looking at this again, maybe it should be selected. If you see the kernel config of TINYDRM_HX8357D, which is also in drm/tiny, it is selecting BACKLIGHT_CLASS_DEVICE.

This driver does it wrong.

> To make things more clear,
>
> 1. hid-appletb-bl is for the backlight of the touchbar. The DRM code remains separate.
> 2. hid-multitouch is to make the touchbar a touch screen. You can still use the driver without the touch functionality.

If your driver does not require this, it shouldn't select or depend on it.

Best regards
Thomas


-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 25 Feb 2025, at 3:05 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
> 
> Hi
> 
>> Am 25.02.25 um 10:07 schrieb Aditya Garg:
>> 
>>>> On 25 Feb 2025, at 2:34 PM, Aditya Garg <gargaditya08@live.com> wrote:
>>> 
>>> 
>>> 
>>>> On 25 Feb 2025, at 1:27 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>>>> 
>>>> Hi
>>>> 
>>>> Am 24.02.25 um 17:58 schrieb Aditya Garg:
>>>> [...]
>>>>>> +config DRM_APPLETBDRM
>>>>>> +    tristate "DRM support for Apple Touch Bars"
>>>>>> +    depends on DRM && USB && MMU
>>>>>> +    select DRM_GEM_SHMEM_HELPER
>>>>>> +    select DRM_KMS_HELPER
>>>>>> +    select HID_APPLETB_BL
>>>>> Btw I have a doubt regarding this dependency. While hid-appletb-bl has made into the linux-next tree, it has still not been merged into Linus' tree, and neither the drm tree I assume. It potentially could cause issues?
>>>> Yes. We cannot merge this driver until we have this symbol in our tree. But that will happen sooner or later.
>>>> 
>>>> More problematic is that your driver selects HID_APPLETB_BL. From what I've seen, this symbol is user configurable, so the driver shouldn't select it. You need to use 'depends on' instead of 'select' here.
>>> Looking at this again, maybe it should be selected. If you see the kernel config of TINYDRM_HX8357D, which is also in drm/tiny, it is selecting BACKLIGHT_CLASS_DEVICE.
> 
> This driver does it wrong.
> 
>> To make things more clear,
>> 
>> 1. hid-appletb-bl is for the backlight of the touchbar. The DRM code remains separate.
>> 2. hid-multitouch is to make the touchbar a touch screen. You can still use the driver without the touch functionality.
> 
> If your driver does not require this, it shouldn't select or depend on it.

Could you explain me in what situations would select be used?

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 25 Feb 2025, at 3:07 PM, Aditya Garg <gargaditya08@live.com> wrote:
> 
> 
> 
>> On 25 Feb 2025, at 3:05 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>> 
>> Hi
>> 
>>>> Am 25.02.25 um 10:07 schrieb Aditya Garg:
>>> 
>>>>> On 25 Feb 2025, at 2:34 PM, Aditya Garg <gargaditya08@live.com> wrote:
>>>> 
>>>> 
>>>> 
>>>>> On 25 Feb 2025, at 1:27 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>>>>> 
>>>>> Hi
>>>>> 
>>>>> Am 24.02.25 um 17:58 schrieb Aditya Garg:
>>>>> [...]
>>>>>>> +config DRM_APPLETBDRM
>>>>>>> +    tristate "DRM support for Apple Touch Bars"
>>>>>>> +    depends on DRM && USB && MMU
>>>>>>> +    select DRM_GEM_SHMEM_HELPER
>>>>>>> +    select DRM_KMS_HELPER
>>>>>>> +    select HID_APPLETB_BL
>>>>>> Btw I have a doubt regarding this dependency. While hid-appletb-bl has made into the linux-next tree, it has still not been merged into Linus' tree, and neither the drm tree I assume. It potentially could cause issues?
>>>>> Yes. We cannot merge this driver until we have this symbol in our tree. But that will happen sooner or later.
>>>>> 
>>>>> More problematic is that your driver selects HID_APPLETB_BL. From what I've seen, this symbol is user configurable, so the driver shouldn't select it. You need to use 'depends on' instead of 'select' here.
>>>> Looking at this again, maybe it should be selected. If you see the kernel config of TINYDRM_HX8357D, which is also in drm/tiny, it is selecting BACKLIGHT_CLASS_DEVICE.
>> 
>> This driver does it wrong.
>> 
>>> To make things more clear,
>>> 
>>> 1. hid-appletb-bl is for the backlight of the touchbar. The DRM code remains separate.
>>> 2. hid-multitouch is to make the touchbar a touch screen. You can still use the driver without the touch functionality.
>> 
>> If your driver does not require this, it shouldn't select or depend on it.
> 
> Could you explain me in what situations would select be used?

Hmm, I got some docs about this, though not very clear, but good enough to make me decide to not include these two in the kconfig.

This also means that the driver can now be merged without pulling linux-next in DRM.

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Thomas Zimmermann]

Hi

Am 24.02.25 um 14:40 schrieb Aditya Garg:
> From: Kerem Karabay <kekrby@gmail.com>
>
> The Touch Bars found on x86 Macs support two USB configurations: one
> where the device presents itself as a HID keyboard and can display
> predefined sets of keys, and one where the operating system has full
> control over what is displayed.
>
> This commit adds support for the display functionality of the second
> configuration. Functionality for the first configuration has been
> merged in the HID tree.
>
> Note that this driver has only been tested on T2 Macs, and only includes
> the USB device ID for these devices. Testing on T1 Macs would be
> appreciated.
>
> Credit goes to Ben (Bingxing) Wang on GitHub for reverse engineering
> most of the protocol.
>
> Also, as requested by Andy, I would like to clarify the use of __packed
> structs in this driver:
>
> - All the packed structs are aligned except for appletbdrm_msg_information.
> - We have to pack appletbdrm_msg_information since it is requirement of
>    the protocol.
> - We compared binaries compiled by keeping the rest structs __packed and
>    not __packed using bloat-o-meter, and __packed was not affecting code
>    generation.
> - To maintain consistency, rest structs have been kept __packed.
>
> Link: https://github.com/imbushuo/DFRDisplayKm
> Signed-off-by: Kerem Karabay <kekrby@gmail.com>
> Co-developed-by: Atharva Tiwari <evepolonium@gmail.com>
> Signed-off-by: Atharva Tiwari <evepolonium@gmail.com>
> Co-developed-by: Aditya Garg <gargaditya08@live.com>
> Signed-off-by: Aditya Garg <gargaditya08@live.com>
> Signed-off-by: Aun-Ali Zaidi <admin@kodeit.net>
> ---
> v2 ->
> - Add the driver to MAINTAINERS.
> - Allocate memory for request and response in plane's atomic-check helper
> - Void the use of drm_fb_blit()
> - Implement atomic_disable
> - Make PRIME work
> - Remove the date field from struct drm_driver
> - intersect damage with dst_clip
> - Register DRM device in appletbdrm_probe
> - Clear the display as the final call in probe
> - Select hid_multitouch as well in kconfig
>
> v3 ->
> - Change commit message to credit Ben (Bingxing) Wang
>
> v4 ->
> - Use "Link:" in commit message
> - Specify why __packed has been used in commit message
> - Use %p4cc instead of %p4ch for errors
> - Add myself to Maintainers
> - Remove #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> - Add missing header files
> - Use return 0; instead of return ret; in static int appletbdrm_send_request
> - Better errno types used in appletbdrm_read_response
> - Use BITS_TO_BYTES() to convert APPLETBDRM_BITS_PER_PIXEL to bytes
> - Remove redundant else in plane_helper_atomic_check
> - Remove unnecessary use of 0xff in request->msg_id = timestamp & 0xff;
> - Remove duplicated struct device in struct appletbdrm_device
> - clear frames_size and request_size as well in primary_plane_helper_atomic_update
> - Allocate using kzalloc instead of kmemdup
> - Use drm_err() instead of dev_err_probe()
> - Avoid clearing drm->mode_config.min_width and height to 0
> - Use put_device() to release the DMA device in appletbdrm_disconnect
>
>   MAINTAINERS                       |   8 +
>   drivers/gpu/drm/tiny/Kconfig      |  14 +
>   drivers/gpu/drm/tiny/Makefile     |   1 +
>   drivers/gpu/drm/tiny/appletbdrm.c | 835 ++++++++++++++++++++++++++++++
>   4 files changed, 858 insertions(+)
>   create mode 100644 drivers/gpu/drm/tiny/appletbdrm.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index efee40ea5..f7c97eb24 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7148,6 +7148,14 @@ S:	Supported
>   T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
>   F:	drivers/gpu/drm/sun4i/sun8i*
>   
> +DRM DRIVER FOR APPLE TOUCH BARS
> +M:	Aun-Ali Zaidi <admin@kodeit.net>
> +M:	Aditya Garg <gargaditya08@live.com>

That's better. Since you did all the work so far, you should be listed 
as maintainer as well, until Ali has done a number of commits. It 
doesn't feel right to list someone as  a maintainer with no changes in 
the driver.

> +L:	dri-devel@lists.freedesktop.org
> +S:	Maintained
> +T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
> +F:	drivers/gpu/drm/tiny/appletbdrm.c
> +
>   DRM DRIVER FOR ARM PL111 CLCD
>   M:	Linus Walleij <linus.walleij@linaro.org>
>   S:	Maintained
> diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
> index 94cbdb133..25471791c 100644
> --- a/drivers/gpu/drm/tiny/Kconfig
> +++ b/drivers/gpu/drm/tiny/Kconfig
> @@ -1,5 +1,19 @@
>   # SPDX-License-Identifier: GPL-2.0-only
>   
> +config DRM_APPLETBDRM
> +	tristate "DRM support for Apple Touch Bars"
> +	depends on DRM && USB && MMU
> +	select DRM_GEM_SHMEM_HELPER
> +	select DRM_KMS_HELPER
> +	select HID_APPLETB_BL
> +	select HID_MULTITOUCH
> +	help
> +	  Say Y here if you want support for the display of Touch Bars on x86
> +	  MacBook Pros.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called appletbdrm.
> +
>   config DRM_ARCPGU
>   	tristate "ARC PGU"
>   	depends on DRM && OF
> diff --git a/drivers/gpu/drm/tiny/Makefile b/drivers/gpu/drm/tiny/Makefile
> index 60816d2eb..0a3a7837a 100644
> --- a/drivers/gpu/drm/tiny/Makefile
> +++ b/drivers/gpu/drm/tiny/Makefile
> @@ -1,5 +1,6 @@
>   # SPDX-License-Identifier: GPL-2.0-only
>   
> +obj-$(CONFIG_DRM_APPLETBDRM)		+= appletbdrm.o
>   obj-$(CONFIG_DRM_ARCPGU)		+= arcpgu.o
>   obj-$(CONFIG_DRM_BOCHS)			+= bochs.o
>   obj-$(CONFIG_DRM_CIRRUS_QEMU)		+= cirrus-qemu.o
> diff --git a/drivers/gpu/drm/tiny/appletbdrm.c b/drivers/gpu/drm/tiny/appletbdrm.c
> new file mode 100644
> index 000000000..59a2b20d4
> --- /dev/null
> +++ b/drivers/gpu/drm/tiny/appletbdrm.c
> @@ -0,0 +1,835 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Apple Touch Bar DRM Driver
> + *
> + * Copyright (c) 2023 Kerem Karabay <kekrby@gmail.com>
> + */
> +
> +#include <linux/align.h>
> +#include <linux/array_size.h>
> +#include <linux/bitops.h>
> +#include <linux/bug.h>
> +#include <linux/container_of.h>
> +#include <linux/dev_printk.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/overflow.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <linux/unaligned.h>
> +#include <linux/usb.h>
> +
> +#include <drm/drm_atomic.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_damage_helper.h>
> +#include <drm/drm_drv.h>
> +#include <drm/drm_encoder.h>
> +#include <drm/drm_format_helper.h>
> +#include <drm/drm_fourcc.h>
> +#include <drm/drm_framebuffer.h>
> +#include <drm/drm_gem_atomic_helper.h>
> +#include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_gem_shmem_helper.h>
> +#include <drm/drm_plane.h>
> +#include <drm/drm_probe_helper.h>
> +
> +#define __APPLETBDRM_MSG_STR4(str4)	((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
> +#define __APPLETBDRM_MSG_TOK4(tok4)	__APPLETBDRM_MSG_STR4(#tok4)
> +
> +#define APPLETBDRM_PIXEL_FORMAT		__APPLETBDRM_MSG_TOK4(RGBA) /* The actual format is BGR888 */
> +#define APPLETBDRM_BITS_PER_PIXEL	24
> +
> +#define APPLETBDRM_MSG_CLEAR_DISPLAY	__APPLETBDRM_MSG_TOK4(CLRD)
> +#define APPLETBDRM_MSG_GET_INFORMATION	__APPLETBDRM_MSG_TOK4(GINF)
> +#define APPLETBDRM_MSG_UPDATE_COMPLETE	__APPLETBDRM_MSG_TOK4(UDCL)
> +#define APPLETBDRM_MSG_SIGNAL_READINESS	__APPLETBDRM_MSG_TOK4(REDY)
> +
> +#define APPLETBDRM_BULK_MSG_TIMEOUT	1000
> +
> +#define drm_to_adev(_drm)		container_of(_drm, struct appletbdrm_device, drm)
> +#define adev_to_udev(adev)		interface_to_usbdev(to_usb_interface(adev->dev))
> +
> +struct appletbdrm_msg_request_header {
> +	__le16 unk_00;
> +	__le16 unk_02;
> +	__le32 unk_04;
> +	__le32 unk_08;
> +	__le32 size;
> +} __packed;
> +
> +struct appletbdrm_msg_response_header {
> +	u8 unk_00[16];
> +	__le32 msg;
> +} __packed;
> +
> +struct appletbdrm_msg_simple_request {
> +	struct appletbdrm_msg_request_header header;
> +	__le32 msg;
> +	u8 unk_14[8];
> +	__le32 size;
> +} __packed;
> +
> +struct appletbdrm_msg_information {
> +	struct appletbdrm_msg_response_header header;
> +	u8 unk_14[12];
> +	__le32 width;
> +	__le32 height;
> +	u8 bits_per_pixel;
> +	__le32 bytes_per_row;
> +	__le32 orientation;
> +	__le32 bitmap_info;
> +	__le32 pixel_format;
> +	__le32 width_inches;	/* floating point */
> +	__le32 height_inches;	/* floating point */
> +} __packed;
> +
> +struct appletbdrm_frame {
> +	__le16 begin_x;
> +	__le16 begin_y;
> +	__le16 width;
> +	__le16 height;
> +	__le32 buf_size;
> +	u8 buf[];
> +} __packed;
> +
> +struct appletbdrm_fb_request_footer {
> +	u8 unk_00[12];
> +	__le32 unk_0c;
> +	u8 unk_10[12];
> +	__le32 unk_1c;
> +	__le64 timestamp;
> +	u8 unk_28[12];
> +	__le32 unk_34;
> +	u8 unk_38[20];
> +	__le32 unk_4c;
> +} __packed;
> +
> +struct appletbdrm_fb_request {
> +	struct appletbdrm_msg_request_header header;
> +	__le16 unk_10;
> +	u8 msg_id;
> +	u8 unk_13[29];
> +	/*
> +	 * Contents of `data`:
> +	 * - struct appletbdrm_frame frames[];
> +	 * - struct appletbdrm_fb_request_footer footer;
> +	 * - padding to make the total size a multiple of 16
> +	 */
> +	u8 data[];
> +} __packed;
> +
> +struct appletbdrm_fb_request_response {
> +	struct appletbdrm_msg_response_header header;
> +	u8 unk_14[12];
> +	__le64 timestamp;
> +} __packed;
> +
> +struct appletbdrm_device {
> +	struct device *dev;

This field should go away, please. There's drm.dev, which contains the 
same address.

So seems to have remove the dmadev field instead, which you'll need for 
dma-buf sharing. Was that a misunderstanding from the last review?

The rest of the driver looks good.

Best regards
Thomas

> +
> +	unsigned int in_ep;
> +	unsigned int out_ep;
> +
> +	unsigned int width;
> +	unsigned int height;
> +
> +	struct drm_device drm;
> +	struct drm_display_mode mode;
> +	struct drm_connector connector;
> +	struct drm_plane primary_plane;
> +	struct drm_crtc crtc;
> +	struct drm_encoder encoder;
> +};
> +
> +struct appletbdrm_plane_state {
> +	struct drm_shadow_plane_state base;
> +	struct appletbdrm_fb_request *request;
> +	struct appletbdrm_fb_request_response *response;
> +	size_t request_size;
> +	size_t frames_size;
> +};
> +
> +static inline struct appletbdrm_plane_state *to_appletbdrm_plane_state(struct drm_plane_state *state)
> +{
> +	return container_of(state, struct appletbdrm_plane_state, base.base);
> +}
> +
> +static int appletbdrm_send_request(struct appletbdrm_device *adev,
> +				   struct appletbdrm_msg_request_header *request, size_t size)
> +{
> +	struct usb_device *udev = adev_to_udev(adev);
> +	struct drm_device *drm = &adev->drm;
> +	int ret, actual_size;
> +
> +	ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, adev->out_ep),
> +			   request, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT);
> +	if (ret) {
> +		drm_err(drm, "Failed to send message (%d)\n", ret);
> +		return ret;
> +	}
> +
> +	if (actual_size != size) {
> +		drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
> +			actual_size, size);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int appletbdrm_read_response(struct appletbdrm_device *adev,
> +				    struct appletbdrm_msg_response_header *response,
> +				    size_t size, __le32 expected_response)
> +{
> +	struct usb_device *udev = adev_to_udev(adev);
> +	struct drm_device *drm = &adev->drm;
> +	int ret, actual_size;
> +	bool readiness_signal_received = false;
> +
> +retry:
> +	ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, adev->in_ep),
> +			   response, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT);
> +	if (ret) {
> +		drm_err(drm, "Failed to read response (%d)\n", ret);
> +		return ret;
> +	}
> +
> +	/*
> +	 * The device responds to the first request sent in a particular
> +	 * timeframe after the USB device configuration is set with a readiness
> +	 * signal, in which case the response should be read again
> +	 */
> +	if (response->msg == APPLETBDRM_MSG_SIGNAL_READINESS) {
> +		if (!readiness_signal_received) {
> +			readiness_signal_received = true;
> +			goto retry;
> +		}
> +
> +		drm_err(drm, "Encountered unexpected readiness signal\n");
> +		return -EINTR;
> +	}
> +
> +	if (actual_size != size) {
> +		drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
> +			actual_size, size);
> +		return -EBADMSG;
> +	}
> +
> +	if (response->msg != expected_response) {
> +		drm_err(drm, "Unexpected response from device (expected %p4cc found %p4cc)\n",
> +			&expected_response, &response->msg);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int appletbdrm_send_msg(struct appletbdrm_device *adev, __le32 msg)
> +{
> +	struct appletbdrm_msg_simple_request *request;
> +	int ret;
> +
> +	request = kzalloc(sizeof(*request), GFP_KERNEL);
> +	if (!request)
> +		return -ENOMEM;
> +
> +	request->header.unk_00 = cpu_to_le16(2);
> +	request->header.unk_02 = cpu_to_le16(0x1512);
> +	request->header.size = cpu_to_le32(sizeof(*request) - sizeof(request->header));
> +	request->msg = msg;
> +	request->size = request->header.size;
> +
> +	ret = appletbdrm_send_request(adev, &request->header, sizeof(*request));
> +
> +	kfree(request);
> +
> +	return ret;
> +}
> +
> +static int appletbdrm_clear_display(struct appletbdrm_device *adev)
> +{
> +	return appletbdrm_send_msg(adev, APPLETBDRM_MSG_CLEAR_DISPLAY);
> +}
> +
> +static int appletbdrm_signal_readiness(struct appletbdrm_device *adev)
> +{
> +	return appletbdrm_send_msg(adev, APPLETBDRM_MSG_SIGNAL_READINESS);
> +}
> +
> +static int appletbdrm_get_information(struct appletbdrm_device *adev)
> +{
> +	struct appletbdrm_msg_information *info;
> +	struct drm_device *drm = &adev->drm;
> +	u8 bits_per_pixel;
> +	__le32 pixel_format;
> +	int ret;
> +
> +	info = kzalloc(sizeof(*info), GFP_KERNEL);
> +	if (!info)
> +		return -ENOMEM;
> +
> +	ret = appletbdrm_send_msg(adev, APPLETBDRM_MSG_GET_INFORMATION);
> +	if (ret)
> +		return ret;
> +
> +	ret = appletbdrm_read_response(adev, &info->header, sizeof(*info),
> +				       APPLETBDRM_MSG_GET_INFORMATION);
> +	if (ret)
> +		goto free_info;
> +
> +	bits_per_pixel = info->bits_per_pixel;
> +	pixel_format = get_unaligned(&info->pixel_format);
> +
> +	adev->width = get_unaligned_le32(&info->width);
> +	adev->height = get_unaligned_le32(&info->height);
> +
> +	if (bits_per_pixel != APPLETBDRM_BITS_PER_PIXEL) {
> +		drm_err(drm, "Encountered unexpected bits per pixel value (%d)\n", bits_per_pixel);
> +		ret = -EINVAL;
> +		goto free_info;
> +	}
> +
> +	if (pixel_format != APPLETBDRM_PIXEL_FORMAT) {
> +		drm_err(drm, "Encountered unknown pixel format (%p4cc)\n", &pixel_format);
> +		ret = -EINVAL;
> +		goto free_info;
> +	}
> +
> +free_info:
> +	kfree(info);
> +
> +	return ret;
> +}
> +
> +static u32 rect_size(struct drm_rect *rect)
> +{
> +	return drm_rect_width(rect) * drm_rect_height(rect) *
> +		(BITS_TO_BYTES(APPLETBDRM_BITS_PER_PIXEL));
> +}
> +
> +static int appletbdrm_connector_helper_get_modes(struct drm_connector *connector)
> +{
> +	struct appletbdrm_device *adev = drm_to_adev(connector->dev);
> +
> +	return drm_connector_helper_get_modes_fixed(connector, &adev->mode);
> +}
> +
> +static const u32 appletbdrm_primary_plane_formats[] = {
> +	DRM_FORMAT_BGR888,
> +	DRM_FORMAT_XRGB8888, /* emulated */
> +};
> +
> +static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
> +						   struct drm_atomic_state *state)
> +{
> +	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
> +	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
> +	struct drm_crtc *new_crtc = new_plane_state->crtc;
> +	struct drm_crtc_state *new_crtc_state = NULL;
> +	struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(new_plane_state);
> +	struct drm_atomic_helper_damage_iter iter;
> +	struct drm_rect damage;
> +	size_t frames_size = 0;
> +	size_t request_size;
> +	int ret;
> +
> +	if (new_crtc)
> +		new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
> +
> +	ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
> +						  DRM_PLANE_NO_SCALING,
> +						  DRM_PLANE_NO_SCALING,
> +						  false, false);
> +	if (ret)
> +		return ret;
> +
> +	if (!new_plane_state->visible)
> +		return 0;
> +
> +	drm_atomic_helper_damage_iter_init(&iter, old_plane_state, new_plane_state);
> +	drm_atomic_for_each_plane_damage(&iter, &damage) {
> +		frames_size += struct_size((struct appletbdrm_frame *)0, buf, rect_size(&damage));
> +	}
> +
> +	if (!frames_size)
> +		return 0;
> +
> +	request_size = ALIGN(sizeof(struct appletbdrm_fb_request) +
> +		       frames_size +
> +		       sizeof(struct appletbdrm_fb_request_footer), 16);
> +
> +	appletbdrm_state->request = kzalloc(request_size, GFP_KERNEL);
> +
> +	if (!appletbdrm_state->request)
> +		return -ENOMEM;
> +
> +	appletbdrm_state->response = kzalloc(sizeof(*appletbdrm_state->response), GFP_KERNEL);
> +
> +	if (!appletbdrm_state->response)
> +		return -ENOMEM;
> +
> +	appletbdrm_state->request_size = request_size;
> +	appletbdrm_state->frames_size = frames_size;
> +
> +	return 0;
> +}
> +
> +static int appletbdrm_flush_damage(struct appletbdrm_device *adev,
> +				   struct drm_plane_state *old_state,
> +				   struct drm_plane_state *state)
> +{
> +	struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state);
> +	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
> +	struct appletbdrm_fb_request_response *response = appletbdrm_state->response;
> +	struct appletbdrm_fb_request_footer *footer;
> +	struct drm_atomic_helper_damage_iter iter;
> +	struct drm_framebuffer *fb = state->fb;
> +	struct appletbdrm_fb_request *request = appletbdrm_state->request;
> +	struct drm_device *drm = &adev->drm;
> +	struct appletbdrm_frame *frame;
> +	u64 timestamp = ktime_get_ns();
> +	struct drm_rect damage;
> +	size_t frames_size = appletbdrm_state->frames_size;
> +	size_t request_size = appletbdrm_state->request_size;
> +	int ret;
> +
> +	if (!frames_size)
> +		return 0;
> +
> +	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
> +	if (ret) {
> +		drm_err(drm, "Failed to start CPU framebuffer access (%d)\n", ret);
> +		goto end_fb_cpu_access;
> +	}
> +
> +	request->header.unk_00 = cpu_to_le16(2);
> +	request->header.unk_02 = cpu_to_le16(0x12);
> +	request->header.unk_04 = cpu_to_le32(9);
> +	request->header.size = cpu_to_le32(request_size - sizeof(request->header));
> +	request->unk_10 = cpu_to_le16(1);
> +	request->msg_id = timestamp;
> +
> +	frame = (struct appletbdrm_frame *)request->data;
> +
> +	drm_atomic_helper_damage_iter_init(&iter, old_state, state);
> +	drm_atomic_for_each_plane_damage(&iter, &damage) {
> +		struct drm_rect dst_clip = state->dst;
> +		struct iosys_map dst = IOSYS_MAP_INIT_VADDR(frame->buf);
> +		u32 buf_size = rect_size(&damage);
> +
> +		if (!drm_rect_intersect(&dst_clip, &damage))
> +			continue;
> +
> +		/*
> +		 * The coordinates need to be translated to the coordinate
> +		 * system the device expects, see the comment in
> +		 * appletbdrm_setup_mode_config
> +		 */
> +		frame->begin_x = cpu_to_le16(damage.y1);
> +		frame->begin_y = cpu_to_le16(adev->height - damage.x2);
> +		frame->width = cpu_to_le16(drm_rect_height(&damage));
> +		frame->height = cpu_to_le16(drm_rect_width(&damage));
> +		frame->buf_size = cpu_to_le32(buf_size);
> +
> +		switch (fb->format->format) {
> +		case DRM_FORMAT_XRGB8888:
> +			drm_fb_xrgb8888_to_bgr888(&dst, NULL, &shadow_plane_state->data[0], fb, &damage, &shadow_plane_state->fmtcnv_state);
> +			break;
> +		default:
> +			drm_fb_memcpy(&dst, NULL, &shadow_plane_state->data[0], fb, &damage);
> +			break;
> +		}
> +
> +		frame = (void *)frame + struct_size(frame, buf, buf_size);
> +	}
> +
> +	footer = (struct appletbdrm_fb_request_footer *)&request->data[frames_size];
> +
> +	footer->unk_0c = cpu_to_le32(0xfffe);
> +	footer->unk_1c = cpu_to_le32(0x80001);
> +	footer->unk_34 = cpu_to_le32(0x80002);
> +	footer->unk_4c = cpu_to_le32(0xffff);
> +	footer->timestamp = cpu_to_le64(timestamp);
> +
> +	ret = appletbdrm_send_request(adev, &request->header, request_size);
> +	if (ret)
> +		goto end_fb_cpu_access;
> +
> +	ret = appletbdrm_read_response(adev, &response->header, sizeof(*response),
> +				       APPLETBDRM_MSG_UPDATE_COMPLETE);
> +	if (ret)
> +		goto end_fb_cpu_access;
> +
> +	if (response->timestamp != footer->timestamp) {
> +		drm_err(drm, "Response timestamp (%llu) doesn't match request timestamp (%llu)\n",
> +			le64_to_cpu(response->timestamp), timestamp);
> +		goto end_fb_cpu_access;
> +	}
> +
> +end_fb_cpu_access:
> +	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
> +
> +	return ret;
> +}
> +
> +static void appletbdrm_primary_plane_helper_atomic_update(struct drm_plane *plane,
> +						     struct drm_atomic_state *old_state)
> +{
> +	struct appletbdrm_device *adev = drm_to_adev(plane->dev);
> +	struct drm_device *drm = plane->dev;
> +	struct drm_plane_state *plane_state = plane->state;
> +	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(old_state, plane);
> +	int idx;
> +
> +	if (!drm_dev_enter(drm, &idx))
> +		return;
> +
> +	appletbdrm_flush_damage(adev, old_plane_state, plane_state);
> +
> +	drm_dev_exit(idx);
> +}
> +
> +static void appletbdrm_primary_plane_helper_atomic_disable(struct drm_plane *plane,
> +							   struct drm_atomic_state *state)
> +{
> +	struct drm_device *dev = plane->dev;
> +	struct appletbdrm_device *adev = drm_to_adev(dev);
> +	int idx;
> +
> +	if (!drm_dev_enter(dev, &idx))
> +		return;
> +
> +	appletbdrm_clear_display(adev);
> +
> +	drm_dev_exit(idx);
> +}
> +
> +static void appletbdrm_primary_plane_reset(struct drm_plane *plane)
> +{
> +	struct appletbdrm_plane_state *appletbdrm_state;
> +
> +	WARN_ON(plane->state);
> +
> +	appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL);
> +	if (!appletbdrm_state)
> +		return;
> +
> +	__drm_gem_reset_shadow_plane(plane, &appletbdrm_state->base);
> +}
> +
> +static struct drm_plane_state *appletbdrm_primary_plane_duplicate_state(struct drm_plane *plane)
> +{
> +	struct drm_shadow_plane_state *new_shadow_plane_state;
> +	struct appletbdrm_plane_state *old_appletbdrm_state;
> +	struct appletbdrm_plane_state *appletbdrm_state;
> +
> +	if (WARN_ON(!plane->state))
> +		return NULL;
> +
> +	old_appletbdrm_state = to_appletbdrm_plane_state(plane->state);
> +	appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL);
> +	if (!appletbdrm_state)
> +		return NULL;
> +
> +	/* Request and response are not duplicated and are allocated in .atomic_check */
> +	appletbdrm_state->request = NULL;
> +	appletbdrm_state->response = NULL;
> +
> +	appletbdrm_state->request_size = 0;
> +	appletbdrm_state->frames_size = 0;
> +
> +	new_shadow_plane_state = &appletbdrm_state->base;
> +
> +	__drm_gem_duplicate_shadow_plane_state(plane, new_shadow_plane_state);
> +
> +	return &new_shadow_plane_state->base;
> +}
> +
> +static void appletbdrm_primary_plane_destroy_state(struct drm_plane *plane,
> +						   struct drm_plane_state *state)
> +{
> +	struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state);
> +
> +	kfree(appletbdrm_state->request);
> +	kfree(appletbdrm_state->response);
> +
> +	__drm_gem_destroy_shadow_plane_state(&appletbdrm_state->base);
> +
> +	kfree(appletbdrm_state);
> +}
> +
> +static const struct drm_plane_helper_funcs appletbdrm_primary_plane_helper_funcs = {
> +	DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
> +	.atomic_check = appletbdrm_primary_plane_helper_atomic_check,
> +	.atomic_update = appletbdrm_primary_plane_helper_atomic_update,
> +	.atomic_disable = appletbdrm_primary_plane_helper_atomic_disable,
> +};
> +
> +static const struct drm_plane_funcs appletbdrm_primary_plane_funcs = {
> +	.update_plane = drm_atomic_helper_update_plane,
> +	.disable_plane = drm_atomic_helper_disable_plane,
> +	.reset = appletbdrm_primary_plane_reset,
> +	.atomic_duplicate_state = appletbdrm_primary_plane_duplicate_state,
> +	.atomic_destroy_state = appletbdrm_primary_plane_destroy_state,
> +	.destroy = drm_plane_cleanup,
> +};
> +
> +static enum drm_mode_status appletbdrm_crtc_helper_mode_valid(struct drm_crtc *crtc,
> +							  const struct drm_display_mode *mode)
> +{
> +	struct appletbdrm_device *adev = drm_to_adev(crtc->dev);
> +
> +	return drm_crtc_helper_mode_valid_fixed(crtc, mode, &adev->mode);
> +}
> +
> +static const struct drm_mode_config_funcs appletbdrm_mode_config_funcs = {
> +	.fb_create = drm_gem_fb_create_with_dirty,
> +	.atomic_check = drm_atomic_helper_check,
> +	.atomic_commit = drm_atomic_helper_commit,
> +};
> +
> +static const struct drm_connector_funcs appletbdrm_connector_funcs = {
> +	.reset = drm_atomic_helper_connector_reset,
> +	.destroy = drm_connector_cleanup,
> +	.fill_modes = drm_helper_probe_single_connector_modes,
> +	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> +	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> +};
> +
> +static const struct drm_connector_helper_funcs appletbdrm_connector_helper_funcs = {
> +	.get_modes = appletbdrm_connector_helper_get_modes,
> +};
> +
> +static const struct drm_crtc_helper_funcs appletbdrm_crtc_helper_funcs = {
> +	.mode_valid = appletbdrm_crtc_helper_mode_valid,
> +};
> +
> +static const struct drm_crtc_funcs appletbdrm_crtc_funcs = {
> +	.reset = drm_atomic_helper_crtc_reset,
> +	.destroy = drm_crtc_cleanup,
> +	.set_config = drm_atomic_helper_set_config,
> +	.page_flip = drm_atomic_helper_page_flip,
> +	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
> +};
> +
> +static const struct drm_encoder_funcs appletbdrm_encoder_funcs = {
> +	.destroy = drm_encoder_cleanup,
> +};
> +
> +static struct drm_gem_object *appletbdrm_driver_gem_prime_import(struct drm_device *dev,
> +								 struct dma_buf *dma_buf)
> +{
> +	struct appletbdrm_device *adev = drm_to_adev(dev);
> +
> +	if (!adev->dev)
> +		return ERR_PTR(-ENODEV);
> +
> +	return drm_gem_prime_import_dev(dev, dma_buf, adev->dev);
> +}
> +
> +DEFINE_DRM_GEM_FOPS(appletbdrm_drm_fops);
> +
> +static const struct drm_driver appletbdrm_drm_driver = {
> +	DRM_GEM_SHMEM_DRIVER_OPS,
> +	.gem_prime_import	= appletbdrm_driver_gem_prime_import,
> +	.name			= "appletbdrm",
> +	.desc			= "Apple Touch Bar DRM Driver",
> +	.major			= 1,
> +	.minor			= 0,
> +	.driver_features	= DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
> +	.fops			= &appletbdrm_drm_fops,
> +};
> +
> +static int appletbdrm_setup_mode_config(struct appletbdrm_device *adev)
> +{
> +	struct drm_connector *connector = &adev->connector;
> +	struct drm_plane *primary_plane;
> +	struct drm_crtc *crtc;
> +	struct drm_encoder *encoder;
> +	struct drm_device *drm = &adev->drm;
> +	int ret;
> +
> +	ret = drmm_mode_config_init(drm);
> +	if (ret) {
> +		drm_err(drm, "Failed to initialize mode configuration\n");
> +		return ret;
> +	}
> +
> +	primary_plane = &adev->primary_plane;
> +	ret = drm_universal_plane_init(drm, primary_plane, 0,
> +				       &appletbdrm_primary_plane_funcs,
> +				       appletbdrm_primary_plane_formats,
> +				       ARRAY_SIZE(appletbdrm_primary_plane_formats),
> +				       NULL,
> +				       DRM_PLANE_TYPE_PRIMARY, NULL);
> +	if (ret) {
> +		drm_err(drm, "Failed to initialize universal plane object\n");
> +		return ret;
> +	}
> +
> +	drm_plane_helper_add(primary_plane, &appletbdrm_primary_plane_helper_funcs);
> +	drm_plane_enable_fb_damage_clips(primary_plane);
> +
> +	crtc = &adev->crtc;
> +	ret = drm_crtc_init_with_planes(drm, crtc, primary_plane, NULL,
> +					&appletbdrm_crtc_funcs, NULL);
> +	if (ret) {
> +		drm_err(drm, "Failed to initialize CRTC object\n");
> +		return ret;
> +	}
> +
> +	drm_crtc_helper_add(crtc, &appletbdrm_crtc_helper_funcs);
> +
> +	encoder = &adev->encoder;
> +	ret = drm_encoder_init(drm, encoder, &appletbdrm_encoder_funcs,
> +			       DRM_MODE_ENCODER_DAC, NULL);
> +	if (ret) {
> +		drm_err(drm, "Failed to initialize encoder\n");
> +		return ret;
> +	}
> +
> +	encoder->possible_crtcs = drm_crtc_mask(crtc);
> +
> +	/*
> +	 * The coordinate system used by the device is different from the
> +	 * coordinate system of the framebuffer in that the x and y axes are
> +	 * swapped, and that the y axis is inverted; so what the device reports
> +	 * as the height is actually the width of the framebuffer and vice
> +	 * versa
> +	 */
> +	drm->mode_config.max_width = max(adev->height, DRM_SHADOW_PLANE_MAX_WIDTH);
> +	drm->mode_config.max_height = max(adev->width, DRM_SHADOW_PLANE_MAX_HEIGHT);
> +	drm->mode_config.preferred_depth = APPLETBDRM_BITS_PER_PIXEL;
> +	drm->mode_config.funcs = &appletbdrm_mode_config_funcs;
> +
> +	adev->mode = (struct drm_display_mode) {
> +		DRM_MODE_INIT(60, adev->height, adev->width,
> +			      DRM_MODE_RES_MM(adev->height, 218),
> +			      DRM_MODE_RES_MM(adev->width, 218))
> +	};
> +
> +	ret = drm_connector_init(drm, connector,
> +				 &appletbdrm_connector_funcs, DRM_MODE_CONNECTOR_USB);
> +	if (ret) {
> +		drm_err(drm, "Failed to initialize connector\n");
> +		return ret;
> +	}
> +
> +	drm_connector_helper_add(connector, &appletbdrm_connector_helper_funcs);
> +
> +	ret = drm_connector_set_panel_orientation(connector,
> +						  DRM_MODE_PANEL_ORIENTATION_RIGHT_UP);
> +	if (ret) {
> +		drm_err(drm, "Failed to set panel orientation\n");
> +		return ret;
> +	}
> +
> +	connector->display_info.non_desktop = true;
> +	ret = drm_object_property_set_value(&connector->base,
> +					    drm->mode_config.non_desktop_property, true);
> +	if (ret) {
> +		drm_err(drm, "Failed to set non-desktop property\n");
> +		return ret;
> +	}
> +
> +	ret = drm_connector_attach_encoder(connector, encoder);
> +
> +	if (ret) {
> +		drm_err(drm, "Failed to initialize simple display pipe\n");
> +		return ret;
> +	}
> +
> +	drm_mode_config_reset(drm);
> +
> +	return 0;
> +}
> +
> +static int appletbdrm_probe(struct usb_interface *intf,
> +			    const struct usb_device_id *id)
> +{
> +	struct usb_endpoint_descriptor *bulk_in, *bulk_out;
> +	struct device *dev = &intf->dev;
> +	struct appletbdrm_device *adev;
> +	struct drm_device *drm;
> +	int ret;
> +
> +	ret = usb_find_common_endpoints(intf->cur_altsetting, &bulk_in, &bulk_out, NULL, NULL);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to find bulk endpoints\n");
> +
> +	adev = devm_drm_dev_alloc(dev, &appletbdrm_drm_driver, struct appletbdrm_device, drm);
> +	if (IS_ERR(adev))
> +		return PTR_ERR(adev);
> +
> +	adev->dev = dev;
> +	adev->in_ep = bulk_in->bEndpointAddress;
> +	adev->out_ep = bulk_out->bEndpointAddress;
> +
> +	drm = &adev->drm;
> +
> +	usb_set_intfdata(intf, adev);
> +
> +	ret = appletbdrm_get_information(adev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to get display information\n");
> +
> +	ret = appletbdrm_signal_readiness(adev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to signal readiness\n");
> +
> +	ret = appletbdrm_setup_mode_config(adev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to setup mode config\n");
> +
> +	ret = drm_dev_register(drm, 0);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to register DRM device\n");
> +
> +	ret = appletbdrm_clear_display(adev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to clear display\n");
> +
> +	return 0;
> +}
> +
> +static void appletbdrm_disconnect(struct usb_interface *intf)
> +{
> +	struct appletbdrm_device *adev = usb_get_intfdata(intf);
> +	struct drm_device *drm = &adev->drm;
> +
> +	put_device(adev->dev);
> +	drm_dev_unplug(drm);
> +	drm_atomic_helper_shutdown(drm);
> +}
> +
> +static void appletbdrm_shutdown(struct usb_interface *intf)
> +{
> +	struct appletbdrm_device *adev = usb_get_intfdata(intf);
> +
> +	/*
> +	 * The framebuffer needs to be cleared on shutdown since its content
> +	 * persists across boots
> +	 */
> +	drm_atomic_helper_shutdown(&adev->drm);
> +}
> +
> +static const struct usb_device_id appletbdrm_usb_id_table[] = {
> +	{ USB_DEVICE_INTERFACE_CLASS(0x05ac, 0x8302, USB_CLASS_AUDIO_VIDEO) },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(usb, appletbdrm_usb_id_table);
> +
> +static struct usb_driver appletbdrm_usb_driver = {
> +	.name		= "appletbdrm",
> +	.probe		= appletbdrm_probe,
> +	.disconnect	= appletbdrm_disconnect,
> +	.shutdown	= appletbdrm_shutdown,
> +	.id_table	= appletbdrm_usb_id_table,
> +};
> +module_usb_driver(appletbdrm_usb_driver);
> +
> +MODULE_AUTHOR("Kerem Karabay <kekrby@gmail.com>");
> +MODULE_DESCRIPTION("Apple Touch Bar DRM Driver");
> +MODULE_LICENSE("GPL");

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 25 Feb 2025, at 1:22 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
> 
> Hi
> 
>> Am 24.02.25 um 14:40 schrieb Aditya Garg:
>> From: Kerem Karabay <kekrby@gmail.com>
>> 
>> The Touch Bars found on x86 Macs support two USB configurations: one
>> where the device presents itself as a HID keyboard and can display
>> predefined sets of keys, and one where the operating system has full
>> control over what is displayed.
>> 
>> This commit adds support for the display functionality of the second
>> configuration. Functionality for the first configuration has been
>> merged in the HID tree.
>> 
>> Note that this driver has only been tested on T2 Macs, and only includes
>> the USB device ID for these devices. Testing on T1 Macs would be
>> appreciated.
>> 
>> Credit goes to Ben (Bingxing) Wang on GitHub for reverse engineering
>> most of the protocol.
>> 
>> Also, as requested by Andy, I would like to clarify the use of __packed
>> structs in this driver:
>> 
>> - All the packed structs are aligned except for appletbdrm_msg_information.
>> - We have to pack appletbdrm_msg_information since it is requirement of
>>   the protocol.
>> - We compared binaries compiled by keeping the rest structs __packed and
>>   not __packed using bloat-o-meter, and __packed was not affecting code
>>   generation.
>> - To maintain consistency, rest structs have been kept __packed.
>> 
>> Link: https://github.com/imbushuo/DFRDisplayKm
>> Signed-off-by: Kerem Karabay <kekrby@gmail.com>
>> Co-developed-by: Atharva Tiwari <evepolonium@gmail.com>
>> Signed-off-by: Atharva Tiwari <evepolonium@gmail.com>
>> Co-developed-by: Aditya Garg <gargaditya08@live.com>
>> Signed-off-by: Aditya Garg <gargaditya08@live.com>
>> Signed-off-by: Aun-Ali Zaidi <admin@kodeit.net>
>> ---
>> v2 ->
>> - Add the driver to MAINTAINERS.
>> - Allocate memory for request and response in plane's atomic-check helper
>> - Void the use of drm_fb_blit()
>> - Implement atomic_disable
>> - Make PRIME work
>> - Remove the date field from struct drm_driver
>> - intersect damage with dst_clip
>> - Register DRM device in appletbdrm_probe
>> - Clear the display as the final call in probe
>> - Select hid_multitouch as well in kconfig
>> 
>> v3 ->
>> - Change commit message to credit Ben (Bingxing) Wang
>> 
>> v4 ->
>> - Use "Link:" in commit message
>> - Specify why __packed has been used in commit message
>> - Use %p4cc instead of %p4ch for errors
>> - Add myself to Maintainers
>> - Remove #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> - Add missing header files
>> - Use return 0; instead of return ret; in static int appletbdrm_send_request
>> - Better errno types used in appletbdrm_read_response
>> - Use BITS_TO_BYTES() to convert APPLETBDRM_BITS_PER_PIXEL to bytes
>> - Remove redundant else in plane_helper_atomic_check
>> - Remove unnecessary use of 0xff in request->msg_id = timestamp & 0xff;
>> - Remove duplicated struct device in struct appletbdrm_device
>> - clear frames_size and request_size as well in primary_plane_helper_atomic_update
>> - Allocate using kzalloc instead of kmemdup
>> - Use drm_err() instead of dev_err_probe()
>> - Avoid clearing drm->mode_config.min_width and height to 0
>> - Use put_device() to release the DMA device in appletbdrm_disconnect
>> 
>>  MAINTAINERS                       |   8 +
>>  drivers/gpu/drm/tiny/Kconfig      |  14 +
>>  drivers/gpu/drm/tiny/Makefile     |   1 +
>>  drivers/gpu/drm/tiny/appletbdrm.c | 835 ++++++++++++++++++++++++++++++
>>  4 files changed, 858 insertions(+)
>>  create mode 100644 drivers/gpu/drm/tiny/appletbdrm.c
>> 
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index efee40ea5..f7c97eb24 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -7148,6 +7148,14 @@ S:    Supported
>>  T:    git https://gitlab.freedesktop.org/drm/misc/kernel.git
>>  F:    drivers/gpu/drm/sun4i/sun8i*
>>  +DRM DRIVER FOR APPLE TOUCH BARS
>> +M:    Aun-Ali Zaidi <admin@kodeit.net>
>> +M:    Aditya Garg <gargaditya08@live.com>
> 
> That's better. Since you did all the work so far, you should be listed as maintainer as well, until Ali has done a number of commits. It doesn't feel right to list someone as  a maintainer with no changes in the driver.

Can we keep both?
> 
>> +L:    dri-devel@lists.freedesktop.org
>> +S:    Maintained
>> +T:    git https://gitlab.freedesktop.org/drm/misc/kernel.git
>> +F:    drivers/gpu/drm/tiny/appletbdrm.c
>> +
>>  DRM DRIVER FOR ARM PL111 CLCD
>>  M:    Linus Walleij <linus.walleij@linaro.org>
>>  S:    Maintained
>> diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
>> index 94cbdb133..25471791c 100644
>> --- a/drivers/gpu/drm/tiny/Kconfig
>> +++ b/drivers/gpu/drm/tiny/Kconfig
>> @@ -1,5 +1,19 @@
>>  # SPDX-License-Identifier: GPL-2.0-only
>>  +config DRM_APPLETBDRM
>> +    tristate "DRM support for Apple Touch Bars"
>> +    depends on DRM && USB && MMU
>> +    select DRM_GEM_SHMEM_HELPER
>> +    select DRM_KMS_HELPER
>> +    select HID_APPLETB_BL
>> +    select HID_MULTITOUCH
>> +    help
>> +      Say Y here if you want support for the display of Touch Bars on x86
>> +      MacBook Pros.
>> +
>> +      To compile this driver as a module, choose M here: the
>> +      module will be called appletbdrm.
>> +
>>  config DRM_ARCPGU
>>      tristate "ARC PGU"
>>      depends on DRM && OF
>> diff --git a/drivers/gpu/drm/tiny/Makefile b/drivers/gpu/drm/tiny/Makefile
>> index 60816d2eb..0a3a7837a 100644
>> --- a/drivers/gpu/drm/tiny/Makefile
>> +++ b/drivers/gpu/drm/tiny/Makefile
>> @@ -1,5 +1,6 @@
>>  # SPDX-License-Identifier: GPL-2.0-only
>>  +obj-$(CONFIG_DRM_APPLETBDRM)        += appletbdrm.o
>>  obj-$(CONFIG_DRM_ARCPGU)        += arcpgu.o
>>  obj-$(CONFIG_DRM_BOCHS)            += bochs.o
>>  obj-$(CONFIG_DRM_CIRRUS_QEMU)        += cirrus-qemu.o
>> diff --git a/drivers/gpu/drm/tiny/appletbdrm.c b/drivers/gpu/drm/tiny/appletbdrm.c
>> new file mode 100644
>> index 000000000..59a2b20d4
>> --- /dev/null
>> +++ b/drivers/gpu/drm/tiny/appletbdrm.c
>> @@ -0,0 +1,835 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Apple Touch Bar DRM Driver
>> + *
>> + * Copyright (c) 2023 Kerem Karabay <kekrby@gmail.com>
>> + */
>> +
>> +#include <linux/align.h>
>> +#include <linux/array_size.h>
>> +#include <linux/bitops.h>
>> +#include <linux/bug.h>
>> +#include <linux/container_of.h>
>> +#include <linux/dev_printk.h>
>> +#include <linux/err.h>
>> +#include <linux/module.h>
>> +#include <linux/overflow.h>
>> +#include <linux/slab.h>
>> +#include <linux/types.h>
>> +#include <linux/unaligned.h>
>> +#include <linux/usb.h>
>> +
>> +#include <drm/drm_atomic.h>
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_crtc.h>
>> +#include <drm/drm_damage_helper.h>
>> +#include <drm/drm_drv.h>
>> +#include <drm/drm_encoder.h>
>> +#include <drm/drm_format_helper.h>
>> +#include <drm/drm_fourcc.h>
>> +#include <drm/drm_framebuffer.h>
>> +#include <drm/drm_gem_atomic_helper.h>
>> +#include <drm/drm_gem_framebuffer_helper.h>
>> +#include <drm/drm_gem_shmem_helper.h>
>> +#include <drm/drm_plane.h>
>> +#include <drm/drm_probe_helper.h>
>> +
>> +#define __APPLETBDRM_MSG_STR4(str4)    ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>> +#define __APPLETBDRM_MSG_TOK4(tok4)    __APPLETBDRM_MSG_STR4(#tok4)
>> +
>> +#define APPLETBDRM_PIXEL_FORMAT        __APPLETBDRM_MSG_TOK4(RGBA) /* The actual format is BGR888 */
>> +#define APPLETBDRM_BITS_PER_PIXEL    24
>> +
>> +#define APPLETBDRM_MSG_CLEAR_DISPLAY    __APPLETBDRM_MSG_TOK4(CLRD)
>> +#define APPLETBDRM_MSG_GET_INFORMATION    __APPLETBDRM_MSG_TOK4(GINF)
>> +#define APPLETBDRM_MSG_UPDATE_COMPLETE    __APPLETBDRM_MSG_TOK4(UDCL)
>> +#define APPLETBDRM_MSG_SIGNAL_READINESS    __APPLETBDRM_MSG_TOK4(REDY)
>> +
>> +#define APPLETBDRM_BULK_MSG_TIMEOUT    1000
>> +
>> +#define drm_to_adev(_drm)        container_of(_drm, struct appletbdrm_device, drm)
>> +#define adev_to_udev(adev)        interface_to_usbdev(to_usb_interface(adev->dev))
>> +
>> +struct appletbdrm_msg_request_header {
>> +    __le16 unk_00;
>> +    __le16 unk_02;
>> +    __le32 unk_04;
>> +    __le32 unk_08;
>> +    __le32 size;
>> +} __packed;
>> +
>> +struct appletbdrm_msg_response_header {
>> +    u8 unk_00[16];
>> +    __le32 msg;
>> +} __packed;
>> +
>> +struct appletbdrm_msg_simple_request {
>> +    struct appletbdrm_msg_request_header header;
>> +    __le32 msg;
>> +    u8 unk_14[8];
>> +    __le32 size;
>> +} __packed;
>> +
>> +struct appletbdrm_msg_information {
>> +    struct appletbdrm_msg_response_header header;
>> +    u8 unk_14[12];
>> +    __le32 width;
>> +    __le32 height;
>> +    u8 bits_per_pixel;
>> +    __le32 bytes_per_row;
>> +    __le32 orientation;
>> +    __le32 bitmap_info;
>> +    __le32 pixel_format;
>> +    __le32 width_inches;    /* floating point */
>> +    __le32 height_inches;    /* floating point */
>> +} __packed;
>> +
>> +struct appletbdrm_frame {
>> +    __le16 begin_x;
>> +    __le16 begin_y;
>> +    __le16 width;
>> +    __le16 height;
>> +    __le32 buf_size;
>> +    u8 buf[];
>> +} __packed;
>> +
>> +struct appletbdrm_fb_request_footer {
>> +    u8 unk_00[12];
>> +    __le32 unk_0c;
>> +    u8 unk_10[12];
>> +    __le32 unk_1c;
>> +    __le64 timestamp;
>> +    u8 unk_28[12];
>> +    __le32 unk_34;
>> +    u8 unk_38[20];
>> +    __le32 unk_4c;
>> +} __packed;
>> +
>> +struct appletbdrm_fb_request {
>> +    struct appletbdrm_msg_request_header header;
>> +    __le16 unk_10;
>> +    u8 msg_id;
>> +    u8 unk_13[29];
>> +    /*
>> +     * Contents of `data`:
>> +     * - struct appletbdrm_frame frames[];
>> +     * - struct appletbdrm_fb_request_footer footer;
>> +     * - padding to make the total size a multiple of 16
>> +     */
>> +    u8 data[];
>> +} __packed;
>> +
>> +struct appletbdrm_fb_request_response {
>> +    struct appletbdrm_msg_response_header header;
>> +    u8 unk_14[12];
>> +    __le64 timestamp;
>> +} __packed;
>> +
>> +struct appletbdrm_device {
>> +    struct device *dev;
> 
> This field should go away, please. There's drm.dev, which contains the same address.
> 
> So seems to have remove the dmadev field instead, which you'll need for dma-buf sharing. Was that a misunderstanding from the last review?

Yeah that was a misunderstanding. I though you meant to remove dmadev.
> 
> The rest of the driver looks good.

Maybe you missed the left over dev_err_probe left in this patch? I'll fix them.
> 
> Best regards
> Thomas
> 
>> +
>> +    unsigned int in_ep;
>> +    unsigned int out_ep;
>> +
>> +    unsigned int width;
>> +    unsigned int height;
>> +
>> +    struct drm_device drm;
>> +    struct drm_display_mode mode;
>> +    struct drm_connector connector;
>> +    struct drm_plane primary_plane;
>> +    struct drm_crtc crtc;
>> +    struct drm_encoder encoder;
>> +};
>> +
>> +struct appletbdrm_plane_state {
>> +    struct drm_shadow_plane_state base;
>> +    struct appletbdrm_fb_request *request;
>> +    struct appletbdrm_fb_request_response *response;
>> +    size_t request_size;
>> +    size_t frames_size;
>> +};
>> +
>> +static inline struct appletbdrm_plane_state *to_appletbdrm_plane_state(struct drm_plane_state *state)
>> +{
>> +    return container_of(state, struct appletbdrm_plane_state, base.base);
>> +}
>> +
>> +static int appletbdrm_send_request(struct appletbdrm_device *adev,
>> +                   struct appletbdrm_msg_request_header *request, size_t size)
>> +{
>> +    struct usb_device *udev = adev_to_udev(adev);
>> +    struct drm_device *drm = &adev->drm;
>> +    int ret, actual_size;
>> +
>> +    ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, adev->out_ep),
>> +               request, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to send message (%d)\n", ret);
>> +        return ret;
>> +    }
>> +
>> +    if (actual_size != size) {
>> +        drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
>> +            actual_size, size);
>> +        return -EIO;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int appletbdrm_read_response(struct appletbdrm_device *adev,
>> +                    struct appletbdrm_msg_response_header *response,
>> +                    size_t size, __le32 expected_response)
>> +{
>> +    struct usb_device *udev = adev_to_udev(adev);
>> +    struct drm_device *drm = &adev->drm;
>> +    int ret, actual_size;
>> +    bool readiness_signal_received = false;
>> +
>> +retry:
>> +    ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, adev->in_ep),
>> +               response, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to read response (%d)\n", ret);
>> +        return ret;
>> +    }
>> +
>> +    /*
>> +     * The device responds to the first request sent in a particular
>> +     * timeframe after the USB device configuration is set with a readiness
>> +     * signal, in which case the response should be read again
>> +     */
>> +    if (response->msg == APPLETBDRM_MSG_SIGNAL_READINESS) {
>> +        if (!readiness_signal_received) {
>> +            readiness_signal_received = true;
>> +            goto retry;
>> +        }
>> +
>> +        drm_err(drm, "Encountered unexpected readiness signal\n");
>> +        return -EINTR;
>> +    }
>> +
>> +    if (actual_size != size) {
>> +        drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
>> +            actual_size, size);
>> +        return -EBADMSG;
>> +    }
>> +
>> +    if (response->msg != expected_response) {
>> +        drm_err(drm, "Unexpected response from device (expected %p4cc found %p4cc)\n",
>> +            &expected_response, &response->msg);
>> +        return -EIO;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int appletbdrm_send_msg(struct appletbdrm_device *adev, __le32 msg)
>> +{
>> +    struct appletbdrm_msg_simple_request *request;
>> +    int ret;
>> +
>> +    request = kzalloc(sizeof(*request), GFP_KERNEL);
>> +    if (!request)
>> +        return -ENOMEM;
>> +
>> +    request->header.unk_00 = cpu_to_le16(2);
>> +    request->header.unk_02 = cpu_to_le16(0x1512);
>> +    request->header.size = cpu_to_le32(sizeof(*request) - sizeof(request->header));
>> +    request->msg = msg;
>> +    request->size = request->header.size;
>> +
>> +    ret = appletbdrm_send_request(adev, &request->header, sizeof(*request));
>> +
>> +    kfree(request);
>> +
>> +    return ret;
>> +}
>> +
>> +static int appletbdrm_clear_display(struct appletbdrm_device *adev)
>> +{
>> +    return appletbdrm_send_msg(adev, APPLETBDRM_MSG_CLEAR_DISPLAY);
>> +}
>> +
>> +static int appletbdrm_signal_readiness(struct appletbdrm_device *adev)
>> +{
>> +    return appletbdrm_send_msg(adev, APPLETBDRM_MSG_SIGNAL_READINESS);
>> +}
>> +
>> +static int appletbdrm_get_information(struct appletbdrm_device *adev)
>> +{
>> +    struct appletbdrm_msg_information *info;
>> +    struct drm_device *drm = &adev->drm;
>> +    u8 bits_per_pixel;
>> +    __le32 pixel_format;
>> +    int ret;
>> +
>> +    info = kzalloc(sizeof(*info), GFP_KERNEL);
>> +    if (!info)
>> +        return -ENOMEM;
>> +
>> +    ret = appletbdrm_send_msg(adev, APPLETBDRM_MSG_GET_INFORMATION);
>> +    if (ret)
>> +        return ret;
>> +
>> +    ret = appletbdrm_read_response(adev, &info->header, sizeof(*info),
>> +                       APPLETBDRM_MSG_GET_INFORMATION);
>> +    if (ret)
>> +        goto free_info;
>> +
>> +    bits_per_pixel = info->bits_per_pixel;
>> +    pixel_format = get_unaligned(&info->pixel_format);
>> +
>> +    adev->width = get_unaligned_le32(&info->width);
>> +    adev->height = get_unaligned_le32(&info->height);
>> +
>> +    if (bits_per_pixel != APPLETBDRM_BITS_PER_PIXEL) {
>> +        drm_err(drm, "Encountered unexpected bits per pixel value (%d)\n", bits_per_pixel);
>> +        ret = -EINVAL;
>> +        goto free_info;
>> +    }
>> +
>> +    if (pixel_format != APPLETBDRM_PIXEL_FORMAT) {
>> +        drm_err(drm, "Encountered unknown pixel format (%p4cc)\n", &pixel_format);
>> +        ret = -EINVAL;
>> +        goto free_info;
>> +    }
>> +
>> +free_info:
>> +    kfree(info);
>> +
>> +    return ret;
>> +}
>> +
>> +static u32 rect_size(struct drm_rect *rect)
>> +{
>> +    return drm_rect_width(rect) * drm_rect_height(rect) *
>> +        (BITS_TO_BYTES(APPLETBDRM_BITS_PER_PIXEL));
>> +}
>> +
>> +static int appletbdrm_connector_helper_get_modes(struct drm_connector *connector)
>> +{
>> +    struct appletbdrm_device *adev = drm_to_adev(connector->dev);
>> +
>> +    return drm_connector_helper_get_modes_fixed(connector, &adev->mode);
>> +}
>> +
>> +static const u32 appletbdrm_primary_plane_formats[] = {
>> +    DRM_FORMAT_BGR888,
>> +    DRM_FORMAT_XRGB8888, /* emulated */
>> +};
>> +
>> +static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
>> +                           struct drm_atomic_state *state)
>> +{
>> +    struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
>> +    struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
>> +    struct drm_crtc *new_crtc = new_plane_state->crtc;
>> +    struct drm_crtc_state *new_crtc_state = NULL;
>> +    struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(new_plane_state);
>> +    struct drm_atomic_helper_damage_iter iter;
>> +    struct drm_rect damage;
>> +    size_t frames_size = 0;
>> +    size_t request_size;
>> +    int ret;
>> +
>> +    if (new_crtc)
>> +        new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
>> +
>> +    ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
>> +                          DRM_PLANE_NO_SCALING,
>> +                          DRM_PLANE_NO_SCALING,
>> +                          false, false);
>> +    if (ret)
>> +        return ret;
>> +
>> +    if (!new_plane_state->visible)
>> +        return 0;
>> +
>> +    drm_atomic_helper_damage_iter_init(&iter, old_plane_state, new_plane_state);
>> +    drm_atomic_for_each_plane_damage(&iter, &damage) {
>> +        frames_size += struct_size((struct appletbdrm_frame *)0, buf, rect_size(&damage));
>> +    }
>> +
>> +    if (!frames_size)
>> +        return 0;
>> +
>> +    request_size = ALIGN(sizeof(struct appletbdrm_fb_request) +
>> +               frames_size +
>> +               sizeof(struct appletbdrm_fb_request_footer), 16);
>> +
>> +    appletbdrm_state->request = kzalloc(request_size, GFP_KERNEL);
>> +
>> +    if (!appletbdrm_state->request)
>> +        return -ENOMEM;
>> +
>> +    appletbdrm_state->response = kzalloc(sizeof(*appletbdrm_state->response), GFP_KERNEL);
>> +
>> +    if (!appletbdrm_state->response)
>> +        return -ENOMEM;
>> +
>> +    appletbdrm_state->request_size = request_size;
>> +    appletbdrm_state->frames_size = frames_size;
>> +
>> +    return 0;
>> +}
>> +
>> +static int appletbdrm_flush_damage(struct appletbdrm_device *adev,
>> +                   struct drm_plane_state *old_state,
>> +                   struct drm_plane_state *state)
>> +{
>> +    struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state);
>> +    struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
>> +    struct appletbdrm_fb_request_response *response = appletbdrm_state->response;
>> +    struct appletbdrm_fb_request_footer *footer;
>> +    struct drm_atomic_helper_damage_iter iter;
>> +    struct drm_framebuffer *fb = state->fb;
>> +    struct appletbdrm_fb_request *request = appletbdrm_state->request;
>> +    struct drm_device *drm = &adev->drm;
>> +    struct appletbdrm_frame *frame;
>> +    u64 timestamp = ktime_get_ns();
>> +    struct drm_rect damage;
>> +    size_t frames_size = appletbdrm_state->frames_size;
>> +    size_t request_size = appletbdrm_state->request_size;
>> +    int ret;
>> +
>> +    if (!frames_size)
>> +        return 0;
>> +
>> +    ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to start CPU framebuffer access (%d)\n", ret);
>> +        goto end_fb_cpu_access;
>> +    }
>> +
>> +    request->header.unk_00 = cpu_to_le16(2);
>> +    request->header.unk_02 = cpu_to_le16(0x12);
>> +    request->header.unk_04 = cpu_to_le32(9);
>> +    request->header.size = cpu_to_le32(request_size - sizeof(request->header));
>> +    request->unk_10 = cpu_to_le16(1);
>> +    request->msg_id = timestamp;
>> +
>> +    frame = (struct appletbdrm_frame *)request->data;
>> +
>> +    drm_atomic_helper_damage_iter_init(&iter, old_state, state);
>> +    drm_atomic_for_each_plane_damage(&iter, &damage) {
>> +        struct drm_rect dst_clip = state->dst;
>> +        struct iosys_map dst = IOSYS_MAP_INIT_VADDR(frame->buf);
>> +        u32 buf_size = rect_size(&damage);
>> +
>> +        if (!drm_rect_intersect(&dst_clip, &damage))
>> +            continue;
>> +
>> +        /*
>> +         * The coordinates need to be translated to the coordinate
>> +         * system the device expects, see the comment in
>> +         * appletbdrm_setup_mode_config
>> +         */
>> +        frame->begin_x = cpu_to_le16(damage.y1);
>> +        frame->begin_y = cpu_to_le16(adev->height - damage.x2);
>> +        frame->width = cpu_to_le16(drm_rect_height(&damage));
>> +        frame->height = cpu_to_le16(drm_rect_width(&damage));
>> +        frame->buf_size = cpu_to_le32(buf_size);
>> +
>> +        switch (fb->format->format) {
>> +        case DRM_FORMAT_XRGB8888:
>> +            drm_fb_xrgb8888_to_bgr888(&dst, NULL, &shadow_plane_state->data[0], fb, &damage, &shadow_plane_state->fmtcnv_state);
>> +            break;
>> +        default:
>> +            drm_fb_memcpy(&dst, NULL, &shadow_plane_state->data[0], fb, &damage);
>> +            break;
>> +        }
>> +
>> +        frame = (void *)frame + struct_size(frame, buf, buf_size);
>> +    }
>> +
>> +    footer = (struct appletbdrm_fb_request_footer *)&request->data[frames_size];
>> +
>> +    footer->unk_0c = cpu_to_le32(0xfffe);
>> +    footer->unk_1c = cpu_to_le32(0x80001);
>> +    footer->unk_34 = cpu_to_le32(0x80002);
>> +    footer->unk_4c = cpu_to_le32(0xffff);
>> +    footer->timestamp = cpu_to_le64(timestamp);
>> +
>> +    ret = appletbdrm_send_request(adev, &request->header, request_size);
>> +    if (ret)
>> +        goto end_fb_cpu_access;
>> +
>> +    ret = appletbdrm_read_response(adev, &response->header, sizeof(*response),
>> +                       APPLETBDRM_MSG_UPDATE_COMPLETE);
>> +    if (ret)
>> +        goto end_fb_cpu_access;
>> +
>> +    if (response->timestamp != footer->timestamp) {
>> +        drm_err(drm, "Response timestamp (%llu) doesn't match request timestamp (%llu)\n",
>> +            le64_to_cpu(response->timestamp), timestamp);
>> +        goto end_fb_cpu_access;
>> +    }
>> +
>> +end_fb_cpu_access:
>> +    drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
>> +
>> +    return ret;
>> +}
>> +
>> +static void appletbdrm_primary_plane_helper_atomic_update(struct drm_plane *plane,
>> +                             struct drm_atomic_state *old_state)
>> +{
>> +    struct appletbdrm_device *adev = drm_to_adev(plane->dev);
>> +    struct drm_device *drm = plane->dev;
>> +    struct drm_plane_state *plane_state = plane->state;
>> +    struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(old_state, plane);
>> +    int idx;
>> +
>> +    if (!drm_dev_enter(drm, &idx))
>> +        return;
>> +
>> +    appletbdrm_flush_damage(adev, old_plane_state, plane_state);
>> +
>> +    drm_dev_exit(idx);
>> +}
>> +
>> +static void appletbdrm_primary_plane_helper_atomic_disable(struct drm_plane *plane,
>> +                               struct drm_atomic_state *state)
>> +{
>> +    struct drm_device *dev = plane->dev;
>> +    struct appletbdrm_device *adev = drm_to_adev(dev);
>> +    int idx;
>> +
>> +    if (!drm_dev_enter(dev, &idx))
>> +        return;
>> +
>> +    appletbdrm_clear_display(adev);
>> +
>> +    drm_dev_exit(idx);
>> +}
>> +
>> +static void appletbdrm_primary_plane_reset(struct drm_plane *plane)
>> +{
>> +    struct appletbdrm_plane_state *appletbdrm_state;
>> +
>> +    WARN_ON(plane->state);
>> +
>> +    appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL);
>> +    if (!appletbdrm_state)
>> +        return;
>> +
>> +    __drm_gem_reset_shadow_plane(plane, &appletbdrm_state->base);
>> +}
>> +
>> +static struct drm_plane_state *appletbdrm_primary_plane_duplicate_state(struct drm_plane *plane)
>> +{
>> +    struct drm_shadow_plane_state *new_shadow_plane_state;
>> +    struct appletbdrm_plane_state *old_appletbdrm_state;
>> +    struct appletbdrm_plane_state *appletbdrm_state;
>> +
>> +    if (WARN_ON(!plane->state))
>> +        return NULL;
>> +
>> +    old_appletbdrm_state = to_appletbdrm_plane_state(plane->state);
>> +    appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL);
>> +    if (!appletbdrm_state)
>> +        return NULL;
>> +
>> +    /* Request and response are not duplicated and are allocated in .atomic_check */
>> +    appletbdrm_state->request = NULL;
>> +    appletbdrm_state->response = NULL;
>> +
>> +    appletbdrm_state->request_size = 0;
>> +    appletbdrm_state->frames_size = 0;
>> +
>> +    new_shadow_plane_state = &appletbdrm_state->base;
>> +
>> +    __drm_gem_duplicate_shadow_plane_state(plane, new_shadow_plane_state);
>> +
>> +    return &new_shadow_plane_state->base;
>> +}
>> +
>> +static void appletbdrm_primary_plane_destroy_state(struct drm_plane *plane,
>> +                           struct drm_plane_state *state)
>> +{
>> +    struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state);
>> +
>> +    kfree(appletbdrm_state->request);
>> +    kfree(appletbdrm_state->response);
>> +
>> +    __drm_gem_destroy_shadow_plane_state(&appletbdrm_state->base);
>> +
>> +    kfree(appletbdrm_state);
>> +}
>> +
>> +static const struct drm_plane_helper_funcs appletbdrm_primary_plane_helper_funcs = {
>> +    DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
>> +    .atomic_check = appletbdrm_primary_plane_helper_atomic_check,
>> +    .atomic_update = appletbdrm_primary_plane_helper_atomic_update,
>> +    .atomic_disable = appletbdrm_primary_plane_helper_atomic_disable,
>> +};
>> +
>> +static const struct drm_plane_funcs appletbdrm_primary_plane_funcs = {
>> +    .update_plane = drm_atomic_helper_update_plane,
>> +    .disable_plane = drm_atomic_helper_disable_plane,
>> +    .reset = appletbdrm_primary_plane_reset,
>> +    .atomic_duplicate_state = appletbdrm_primary_plane_duplicate_state,
>> +    .atomic_destroy_state = appletbdrm_primary_plane_destroy_state,
>> +    .destroy = drm_plane_cleanup,
>> +};
>> +
>> +static enum drm_mode_status appletbdrm_crtc_helper_mode_valid(struct drm_crtc *crtc,
>> +                              const struct drm_display_mode *mode)
>> +{
>> +    struct appletbdrm_device *adev = drm_to_adev(crtc->dev);
>> +
>> +    return drm_crtc_helper_mode_valid_fixed(crtc, mode, &adev->mode);
>> +}
>> +
>> +static const struct drm_mode_config_funcs appletbdrm_mode_config_funcs = {
>> +    .fb_create = drm_gem_fb_create_with_dirty,
>> +    .atomic_check = drm_atomic_helper_check,
>> +    .atomic_commit = drm_atomic_helper_commit,
>> +};
>> +
>> +static const struct drm_connector_funcs appletbdrm_connector_funcs = {
>> +    .reset = drm_atomic_helper_connector_reset,
>> +    .destroy = drm_connector_cleanup,
>> +    .fill_modes = drm_helper_probe_single_connector_modes,
>> +    .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
>> +    .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
>> +};
>> +
>> +static const struct drm_connector_helper_funcs appletbdrm_connector_helper_funcs = {
>> +    .get_modes = appletbdrm_connector_helper_get_modes,
>> +};
>> +
>> +static const struct drm_crtc_helper_funcs appletbdrm_crtc_helper_funcs = {
>> +    .mode_valid = appletbdrm_crtc_helper_mode_valid,
>> +};
>> +
>> +static const struct drm_crtc_funcs appletbdrm_crtc_funcs = {
>> +    .reset = drm_atomic_helper_crtc_reset,
>> +    .destroy = drm_crtc_cleanup,
>> +    .set_config = drm_atomic_helper_set_config,
>> +    .page_flip = drm_atomic_helper_page_flip,
>> +    .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
>> +    .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
>> +};
>> +
>> +static const struct drm_encoder_funcs appletbdrm_encoder_funcs = {
>> +    .destroy = drm_encoder_cleanup,
>> +};
>> +
>> +static struct drm_gem_object *appletbdrm_driver_gem_prime_import(struct drm_device *dev,
>> +                                 struct dma_buf *dma_buf)
>> +{
>> +    struct appletbdrm_device *adev = drm_to_adev(dev);
>> +
>> +    if (!adev->dev)
>> +        return ERR_PTR(-ENODEV);
>> +
>> +    return drm_gem_prime_import_dev(dev, dma_buf, adev->dev);
>> +}
>> +
>> +DEFINE_DRM_GEM_FOPS(appletbdrm_drm_fops);
>> +
>> +static const struct drm_driver appletbdrm_drm_driver = {
>> +    DRM_GEM_SHMEM_DRIVER_OPS,
>> +    .gem_prime_import    = appletbdrm_driver_gem_prime_import,
>> +    .name            = "appletbdrm",
>> +    .desc            = "Apple Touch Bar DRM Driver",
>> +    .major            = 1,
>> +    .minor            = 0,
>> +    .driver_features    = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
>> +    .fops            = &appletbdrm_drm_fops,
>> +};
>> +
>> +static int appletbdrm_setup_mode_config(struct appletbdrm_device *adev)
>> +{
>> +    struct drm_connector *connector = &adev->connector;
>> +    struct drm_plane *primary_plane;
>> +    struct drm_crtc *crtc;
>> +    struct drm_encoder *encoder;
>> +    struct drm_device *drm = &adev->drm;
>> +    int ret;
>> +
>> +    ret = drmm_mode_config_init(drm);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to initialize mode configuration\n");
>> +        return ret;
>> +    }
>> +
>> +    primary_plane = &adev->primary_plane;
>> +    ret = drm_universal_plane_init(drm, primary_plane, 0,
>> +                       &appletbdrm_primary_plane_funcs,
>> +                       appletbdrm_primary_plane_formats,
>> +                       ARRAY_SIZE(appletbdrm_primary_plane_formats),
>> +                       NULL,
>> +                       DRM_PLANE_TYPE_PRIMARY, NULL);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to initialize universal plane object\n");
>> +        return ret;
>> +    }
>> +
>> +    drm_plane_helper_add(primary_plane, &appletbdrm_primary_plane_helper_funcs);
>> +    drm_plane_enable_fb_damage_clips(primary_plane);
>> +
>> +    crtc = &adev->crtc;
>> +    ret = drm_crtc_init_with_planes(drm, crtc, primary_plane, NULL,
>> +                    &appletbdrm_crtc_funcs, NULL);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to initialize CRTC object\n");
>> +        return ret;
>> +    }
>> +
>> +    drm_crtc_helper_add(crtc, &appletbdrm_crtc_helper_funcs);
>> +
>> +    encoder = &adev->encoder;
>> +    ret = drm_encoder_init(drm, encoder, &appletbdrm_encoder_funcs,
>> +                   DRM_MODE_ENCODER_DAC, NULL);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to initialize encoder\n");
>> +        return ret;
>> +    }
>> +
>> +    encoder->possible_crtcs = drm_crtc_mask(crtc);
>> +
>> +    /*
>> +     * The coordinate system used by the device is different from the
>> +     * coordinate system of the framebuffer in that the x and y axes are
>> +     * swapped, and that the y axis is inverted; so what the device reports
>> +     * as the height is actually the width of the framebuffer and vice
>> +     * versa
>> +     */
>> +    drm->mode_config.max_width = max(adev->height, DRM_SHADOW_PLANE_MAX_WIDTH);
>> +    drm->mode_config.max_height = max(adev->width, DRM_SHADOW_PLANE_MAX_HEIGHT);
>> +    drm->mode_config.preferred_depth = APPLETBDRM_BITS_PER_PIXEL;
>> +    drm->mode_config.funcs = &appletbdrm_mode_config_funcs;
>> +
>> +    adev->mode = (struct drm_display_mode) {
>> +        DRM_MODE_INIT(60, adev->height, adev->width,
>> +                  DRM_MODE_RES_MM(adev->height, 218),
>> +                  DRM_MODE_RES_MM(adev->width, 218))
>> +    };
>> +
>> +    ret = drm_connector_init(drm, connector,
>> +                 &appletbdrm_connector_funcs, DRM_MODE_CONNECTOR_USB);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to initialize connector\n");
>> +        return ret;
>> +    }
>> +
>> +    drm_connector_helper_add(connector, &appletbdrm_connector_helper_funcs);
>> +
>> +    ret = drm_connector_set_panel_orientation(connector,
>> +                          DRM_MODE_PANEL_ORIENTATION_RIGHT_UP);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to set panel orientation\n");
>> +        return ret;
>> +    }
>> +
>> +    connector->display_info.non_desktop = true;
>> +    ret = drm_object_property_set_value(&connector->base,
>> +                        drm->mode_config.non_desktop_property, true);
>> +    if (ret) {
>> +        drm_err(drm, "Failed to set non-desktop property\n");
>> +        return ret;
>> +    }
>> +
>> +    ret = drm_connector_attach_encoder(connector, encoder);
>> +
>> +    if (ret) {
>> +        drm_err(drm, "Failed to initialize simple display pipe\n");
>> +        return ret;
>> +    }
>> +
>> +    drm_mode_config_reset(drm);
>> +
>> +    return 0;
>> +}
>> +
>> +static int appletbdrm_probe(struct usb_interface *intf,
>> +                const struct usb_device_id *id)
>> +{
>> +    struct usb_endpoint_descriptor *bulk_in, *bulk_out;
>> +    struct device *dev = &intf->dev;
>> +    struct appletbdrm_device *adev;
>> +    struct drm_device *drm;
>> +    int ret;
>> +
>> +    ret = usb_find_common_endpoints(intf->cur_altsetting, &bulk_in, &bulk_out, NULL, NULL);
>> +    if (ret)
>> +        return dev_err_probe(dev, ret, "Failed to find bulk endpoints\n");
>> +
>> +    adev = devm_drm_dev_alloc(dev, &appletbdrm_drm_driver, struct appletbdrm_device, drm);
>> +    if (IS_ERR(adev))
>> +        return PTR_ERR(adev);
>> +
>> +    adev->dev = dev;
>> +    adev->in_ep = bulk_in->bEndpointAddress;
>> +    adev->out_ep = bulk_out->bEndpointAddress;
>> +
>> +    drm = &adev->drm;
>> +
>> +    usb_set_intfdata(intf, adev);
>> +
>> +    ret = appletbdrm_get_information(adev);
>> +    if (ret)
>> +        return dev_err_probe(dev, ret, "Failed to get display information\n");
>> +
>> +    ret = appletbdrm_signal_readiness(adev);
>> +    if (ret)
>> +        return dev_err_probe(dev, ret, "Failed to signal readiness\n");
>> +
>> +    ret = appletbdrm_setup_mode_config(adev);
>> +    if (ret)
>> +        return dev_err_probe(dev, ret, "Failed to setup mode config\n");
>> +
>> +    ret = drm_dev_register(drm, 0);
>> +    if (ret)
>> +        return dev_err_probe(dev, ret, "Failed to register DRM device\n");
>> +
>> +    ret = appletbdrm_clear_display(adev);
>> +    if (ret)
>> +        return dev_err_probe(dev, ret, "Failed to clear display\n");
>> +
>> +    return 0;
>> +}
>> +
>> +static void appletbdrm_disconnect(struct usb_interface *intf)
>> +{
>> +    struct appletbdrm_device *adev = usb_get_intfdata(intf);
>> +    struct drm_device *drm = &adev->drm;
>> +
>> +    put_device(adev->dev);
>> +    drm_dev_unplug(drm);
>> +    drm_atomic_helper_shutdown(drm);
>> +}
>> +
>> +static void appletbdrm_shutdown(struct usb_interface *intf)
>> +{
>> +    struct appletbdrm_device *adev = usb_get_intfdata(intf);
>> +
>> +    /*
>> +     * The framebuffer needs to be cleared on shutdown since its content
>> +     * persists across boots
>> +     */
>> +    drm_atomic_helper_shutdown(&adev->drm);
>> +}
>> +
>> +static const struct usb_device_id appletbdrm_usb_id_table[] = {
>> +    { USB_DEVICE_INTERFACE_CLASS(0x05ac, 0x8302, USB_CLASS_AUDIO_VIDEO) },
>> +    {}
>> +};
>> +MODULE_DEVICE_TABLE(usb, appletbdrm_usb_id_table);
>> +
>> +static struct usb_driver appletbdrm_usb_driver = {
>> +    .name        = "appletbdrm",
>> +    .probe        = appletbdrm_probe,
>> +    .disconnect    = appletbdrm_disconnect,
>> +    .shutdown    = appletbdrm_shutdown,
>> +    .id_table    = appletbdrm_usb_id_table,
>> +};
>> +module_usb_driver(appletbdrm_usb_driver);
>> +
>> +MODULE_AUTHOR("Kerem Karabay <kekrby@gmail.com>");
>> +MODULE_DESCRIPTION("Apple Touch Bar DRM Driver");
>> +MODULE_LICENSE("GPL");
> 
> --
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Frankenstrasse 146, 90461 Nuernberg, Germany
> GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
> HRB 36809 (AG Nuernberg)
> 

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Thomas Zimmermann]

Hi

Am 25.02.25 um 09:00 schrieb Aditya Garg:
>
>> On 25 Feb 2025, at 1:22 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>>
>> Hi
>>
>>> Am 24.02.25 um 14:40 schrieb Aditya Garg:
>>> From: Kerem Karabay <kekrby@gmail.com>
>>>
>>> The Touch Bars found on x86 Macs support two USB configurations: one
>>> where the device presents itself as a HID keyboard and can display
>>> predefined sets of keys, and one where the operating system has full
>>> control over what is displayed.
>>>
>>> This commit adds support for the display functionality of the second
>>> configuration. Functionality for the first configuration has been
>>> merged in the HID tree.
>>>
>>> Note that this driver has only been tested on T2 Macs, and only includes
>>> the USB device ID for these devices. Testing on T1 Macs would be
>>> appreciated.
>>>
>>> Credit goes to Ben (Bingxing) Wang on GitHub for reverse engineering
>>> most of the protocol.
>>>
>>> Also, as requested by Andy, I would like to clarify the use of __packed
>>> structs in this driver:
>>>
>>> - All the packed structs are aligned except for appletbdrm_msg_information.
>>> - We have to pack appletbdrm_msg_information since it is requirement of
>>>    the protocol.
>>> - We compared binaries compiled by keeping the rest structs __packed and
>>>    not __packed using bloat-o-meter, and __packed was not affecting code
>>>    generation.
>>> - To maintain consistency, rest structs have been kept __packed.
>>>
>>> Link: https://github.com/imbushuo/DFRDisplayKm
>>> Signed-off-by: Kerem Karabay <kekrby@gmail.com>
>>> Co-developed-by: Atharva Tiwari <evepolonium@gmail.com>
>>> Signed-off-by: Atharva Tiwari <evepolonium@gmail.com>
>>> Co-developed-by: Aditya Garg <gargaditya08@live.com>
>>> Signed-off-by: Aditya Garg <gargaditya08@live.com>
>>> Signed-off-by: Aun-Ali Zaidi <admin@kodeit.net>
>>> ---
>>> v2 ->
>>> - Add the driver to MAINTAINERS.
>>> - Allocate memory for request and response in plane's atomic-check helper
>>> - Void the use of drm_fb_blit()
>>> - Implement atomic_disable
>>> - Make PRIME work
>>> - Remove the date field from struct drm_driver
>>> - intersect damage with dst_clip
>>> - Register DRM device in appletbdrm_probe
>>> - Clear the display as the final call in probe
>>> - Select hid_multitouch as well in kconfig
>>>
>>> v3 ->
>>> - Change commit message to credit Ben (Bingxing) Wang
>>>
>>> v4 ->
>>> - Use "Link:" in commit message
>>> - Specify why __packed has been used in commit message
>>> - Use %p4cc instead of %p4ch for errors
>>> - Add myself to Maintainers
>>> - Remove #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>>> - Add missing header files
>>> - Use return 0; instead of return ret; in static int appletbdrm_send_request
>>> - Better errno types used in appletbdrm_read_response
>>> - Use BITS_TO_BYTES() to convert APPLETBDRM_BITS_PER_PIXEL to bytes
>>> - Remove redundant else in plane_helper_atomic_check
>>> - Remove unnecessary use of 0xff in request->msg_id = timestamp & 0xff;
>>> - Remove duplicated struct device in struct appletbdrm_device
>>> - clear frames_size and request_size as well in primary_plane_helper_atomic_update
>>> - Allocate using kzalloc instead of kmemdup
>>> - Use drm_err() instead of dev_err_probe()
>>> - Avoid clearing drm->mode_config.min_width and height to 0
>>> - Use put_device() to release the DMA device in appletbdrm_disconnect
>>>
>>>   MAINTAINERS                       |   8 +
>>>   drivers/gpu/drm/tiny/Kconfig      |  14 +
>>>   drivers/gpu/drm/tiny/Makefile     |   1 +
>>>   drivers/gpu/drm/tiny/appletbdrm.c | 835 ++++++++++++++++++++++++++++++
>>>   4 files changed, 858 insertions(+)
>>>   create mode 100644 drivers/gpu/drm/tiny/appletbdrm.c
>>>
>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>> index efee40ea5..f7c97eb24 100644
>>> --- a/MAINTAINERS
>>> +++ b/MAINTAINERS
>>> @@ -7148,6 +7148,14 @@ S:    Supported
>>>   T:    git https://gitlab.freedesktop.org/drm/misc/kernel.git
>>>   F:    drivers/gpu/drm/sun4i/sun8i*
>>>   +DRM DRIVER FOR APPLE TOUCH BARS
>>> +M:    Aun-Ali Zaidi <admin@kodeit.net>
>>> +M:    Aditya Garg <gargaditya08@live.com>
>> That's better. Since you did all the work so far, you should be listed as maintainer as well, until Ali has done a number of commits. It doesn't feel right to list someone as  a maintainer with no changes in the driver.
> Can we keep both?

Sure, of course.

>>> +L:    dri-devel@lists.freedesktop.org
>>> +S:    Maintained
>>> +T:    git https://gitlab.freedesktop.org/drm/misc/kernel.git
>>> +F:    drivers/gpu/drm/tiny/appletbdrm.c
>>> +
>>>   DRM DRIVER FOR ARM PL111 CLCD
>>>   M:    Linus Walleij <linus.walleij@linaro.org>
>>>   S:    Maintained
>>> diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
>>> index 94cbdb133..25471791c 100644
>>> --- a/drivers/gpu/drm/tiny/Kconfig
>>> +++ b/drivers/gpu/drm/tiny/Kconfig
>>> @@ -1,5 +1,19 @@
>>>   # SPDX-License-Identifier: GPL-2.0-only
>>>   +config DRM_APPLETBDRM
>>> +    tristate "DRM support for Apple Touch Bars"
>>> +    depends on DRM && USB && MMU
>>> +    select DRM_GEM_SHMEM_HELPER
>>> +    select DRM_KMS_HELPER
>>> +    select HID_APPLETB_BL
>>> +    select HID_MULTITOUCH
>>> +    help
>>> +      Say Y here if you want support for the display of Touch Bars on x86
>>> +      MacBook Pros.
>>> +
>>> +      To compile this driver as a module, choose M here: the
>>> +      module will be called appletbdrm.
>>> +
>>>   config DRM_ARCPGU
>>>       tristate "ARC PGU"
>>>       depends on DRM && OF
>>> diff --git a/drivers/gpu/drm/tiny/Makefile b/drivers/gpu/drm/tiny/Makefile
>>> index 60816d2eb..0a3a7837a 100644
>>> --- a/drivers/gpu/drm/tiny/Makefile
>>> +++ b/drivers/gpu/drm/tiny/Makefile
>>> @@ -1,5 +1,6 @@
>>>   # SPDX-License-Identifier: GPL-2.0-only
>>>   +obj-$(CONFIG_DRM_APPLETBDRM)        += appletbdrm.o
>>>   obj-$(CONFIG_DRM_ARCPGU)        += arcpgu.o
>>>   obj-$(CONFIG_DRM_BOCHS)            += bochs.o
>>>   obj-$(CONFIG_DRM_CIRRUS_QEMU)        += cirrus-qemu.o
>>> diff --git a/drivers/gpu/drm/tiny/appletbdrm.c b/drivers/gpu/drm/tiny/appletbdrm.c
>>> new file mode 100644
>>> index 000000000..59a2b20d4
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/tiny/appletbdrm.c
>>> @@ -0,0 +1,835 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Apple Touch Bar DRM Driver
>>> + *
>>> + * Copyright (c) 2023 Kerem Karabay <kekrby@gmail.com>
>>> + */
>>> +
>>> +#include <linux/align.h>
>>> +#include <linux/array_size.h>
>>> +#include <linux/bitops.h>
>>> +#include <linux/bug.h>
>>> +#include <linux/container_of.h>
>>> +#include <linux/dev_printk.h>
>>> +#include <linux/err.h>
>>> +#include <linux/module.h>
>>> +#include <linux/overflow.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/types.h>
>>> +#include <linux/unaligned.h>
>>> +#include <linux/usb.h>
>>> +
>>> +#include <drm/drm_atomic.h>
>>> +#include <drm/drm_atomic_helper.h>
>>> +#include <drm/drm_crtc.h>
>>> +#include <drm/drm_damage_helper.h>
>>> +#include <drm/drm_drv.h>
>>> +#include <drm/drm_encoder.h>
>>> +#include <drm/drm_format_helper.h>
>>> +#include <drm/drm_fourcc.h>
>>> +#include <drm/drm_framebuffer.h>
>>> +#include <drm/drm_gem_atomic_helper.h>
>>> +#include <drm/drm_gem_framebuffer_helper.h>
>>> +#include <drm/drm_gem_shmem_helper.h>
>>> +#include <drm/drm_plane.h>
>>> +#include <drm/drm_probe_helper.h>
>>> +
>>> +#define __APPLETBDRM_MSG_STR4(str4)    ((__le32 __force)((str4[0] << 24) | (str4[1] << 16) | (str4[2] << 8) | str4[3]))
>>> +#define __APPLETBDRM_MSG_TOK4(tok4)    __APPLETBDRM_MSG_STR4(#tok4)
>>> +
>>> +#define APPLETBDRM_PIXEL_FORMAT        __APPLETBDRM_MSG_TOK4(RGBA) /* The actual format is BGR888 */
>>> +#define APPLETBDRM_BITS_PER_PIXEL    24
>>> +
>>> +#define APPLETBDRM_MSG_CLEAR_DISPLAY    __APPLETBDRM_MSG_TOK4(CLRD)
>>> +#define APPLETBDRM_MSG_GET_INFORMATION    __APPLETBDRM_MSG_TOK4(GINF)
>>> +#define APPLETBDRM_MSG_UPDATE_COMPLETE    __APPLETBDRM_MSG_TOK4(UDCL)
>>> +#define APPLETBDRM_MSG_SIGNAL_READINESS    __APPLETBDRM_MSG_TOK4(REDY)
>>> +
>>> +#define APPLETBDRM_BULK_MSG_TIMEOUT    1000
>>> +
>>> +#define drm_to_adev(_drm)        container_of(_drm, struct appletbdrm_device, drm)
>>> +#define adev_to_udev(adev)        interface_to_usbdev(to_usb_interface(adev->dev))
>>> +
>>> +struct appletbdrm_msg_request_header {
>>> +    __le16 unk_00;
>>> +    __le16 unk_02;
>>> +    __le32 unk_04;
>>> +    __le32 unk_08;
>>> +    __le32 size;
>>> +} __packed;
>>> +
>>> +struct appletbdrm_msg_response_header {
>>> +    u8 unk_00[16];
>>> +    __le32 msg;
>>> +} __packed;
>>> +
>>> +struct appletbdrm_msg_simple_request {
>>> +    struct appletbdrm_msg_request_header header;
>>> +    __le32 msg;
>>> +    u8 unk_14[8];
>>> +    __le32 size;
>>> +} __packed;
>>> +
>>> +struct appletbdrm_msg_information {
>>> +    struct appletbdrm_msg_response_header header;
>>> +    u8 unk_14[12];
>>> +    __le32 width;
>>> +    __le32 height;
>>> +    u8 bits_per_pixel;
>>> +    __le32 bytes_per_row;
>>> +    __le32 orientation;
>>> +    __le32 bitmap_info;
>>> +    __le32 pixel_format;
>>> +    __le32 width_inches;    /* floating point */
>>> +    __le32 height_inches;    /* floating point */
>>> +} __packed;
>>> +
>>> +struct appletbdrm_frame {
>>> +    __le16 begin_x;
>>> +    __le16 begin_y;
>>> +    __le16 width;
>>> +    __le16 height;
>>> +    __le32 buf_size;
>>> +    u8 buf[];
>>> +} __packed;
>>> +
>>> +struct appletbdrm_fb_request_footer {
>>> +    u8 unk_00[12];
>>> +    __le32 unk_0c;
>>> +    u8 unk_10[12];
>>> +    __le32 unk_1c;
>>> +    __le64 timestamp;
>>> +    u8 unk_28[12];
>>> +    __le32 unk_34;
>>> +    u8 unk_38[20];
>>> +    __le32 unk_4c;
>>> +} __packed;
>>> +
>>> +struct appletbdrm_fb_request {
>>> +    struct appletbdrm_msg_request_header header;
>>> +    __le16 unk_10;
>>> +    u8 msg_id;
>>> +    u8 unk_13[29];
>>> +    /*
>>> +     * Contents of `data`:
>>> +     * - struct appletbdrm_frame frames[];
>>> +     * - struct appletbdrm_fb_request_footer footer;
>>> +     * - padding to make the total size a multiple of 16
>>> +     */
>>> +    u8 data[];
>>> +} __packed;
>>> +
>>> +struct appletbdrm_fb_request_response {
>>> +    struct appletbdrm_msg_response_header header;
>>> +    u8 unk_14[12];
>>> +    __le64 timestamp;
>>> +} __packed;
>>> +
>>> +struct appletbdrm_device {
>>> +    struct device *dev;
>> This field should go away, please. There's drm.dev, which contains the same address.
>>
>> So seems to have remove the dmadev field instead, which you'll need for dma-buf sharing. Was that a misunderstanding from the last review?
> Yeah that was a misunderstanding. I though you meant to remove dmadev.
>> The rest of the driver looks good.
> Maybe you missed the left over dev_err_probe left in this patch? I'll fix them.

Sure.

Best regards
Thomas

>> Best regards
>> Thomas
>>
>>> +
>>> +    unsigned int in_ep;
>>> +    unsigned int out_ep;
>>> +
>>> +    unsigned int width;
>>> +    unsigned int height;
>>> +
>>> +    struct drm_device drm;
>>> +    struct drm_display_mode mode;
>>> +    struct drm_connector connector;
>>> +    struct drm_plane primary_plane;
>>> +    struct drm_crtc crtc;
>>> +    struct drm_encoder encoder;
>>> +};
>>> +
>>> +struct appletbdrm_plane_state {
>>> +    struct drm_shadow_plane_state base;
>>> +    struct appletbdrm_fb_request *request;
>>> +    struct appletbdrm_fb_request_response *response;
>>> +    size_t request_size;
>>> +    size_t frames_size;
>>> +};
>>> +
>>> +static inline struct appletbdrm_plane_state *to_appletbdrm_plane_state(struct drm_plane_state *state)
>>> +{
>>> +    return container_of(state, struct appletbdrm_plane_state, base.base);
>>> +}
>>> +
>>> +static int appletbdrm_send_request(struct appletbdrm_device *adev,
>>> +                   struct appletbdrm_msg_request_header *request, size_t size)
>>> +{
>>> +    struct usb_device *udev = adev_to_udev(adev);
>>> +    struct drm_device *drm = &adev->drm;
>>> +    int ret, actual_size;
>>> +
>>> +    ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, adev->out_ep),
>>> +               request, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to send message (%d)\n", ret);
>>> +        return ret;
>>> +    }
>>> +
>>> +    if (actual_size != size) {
>>> +        drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
>>> +            actual_size, size);
>>> +        return -EIO;
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int appletbdrm_read_response(struct appletbdrm_device *adev,
>>> +                    struct appletbdrm_msg_response_header *response,
>>> +                    size_t size, __le32 expected_response)
>>> +{
>>> +    struct usb_device *udev = adev_to_udev(adev);
>>> +    struct drm_device *drm = &adev->drm;
>>> +    int ret, actual_size;
>>> +    bool readiness_signal_received = false;
>>> +
>>> +retry:
>>> +    ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, adev->in_ep),
>>> +               response, size, &actual_size, APPLETBDRM_BULK_MSG_TIMEOUT);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to read response (%d)\n", ret);
>>> +        return ret;
>>> +    }
>>> +
>>> +    /*
>>> +     * The device responds to the first request sent in a particular
>>> +     * timeframe after the USB device configuration is set with a readiness
>>> +     * signal, in which case the response should be read again
>>> +     */
>>> +    if (response->msg == APPLETBDRM_MSG_SIGNAL_READINESS) {
>>> +        if (!readiness_signal_received) {
>>> +            readiness_signal_received = true;
>>> +            goto retry;
>>> +        }
>>> +
>>> +        drm_err(drm, "Encountered unexpected readiness signal\n");
>>> +        return -EINTR;
>>> +    }
>>> +
>>> +    if (actual_size != size) {
>>> +        drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
>>> +            actual_size, size);
>>> +        return -EBADMSG;
>>> +    }
>>> +
>>> +    if (response->msg != expected_response) {
>>> +        drm_err(drm, "Unexpected response from device (expected %p4cc found %p4cc)\n",
>>> +            &expected_response, &response->msg);
>>> +        return -EIO;
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int appletbdrm_send_msg(struct appletbdrm_device *adev, __le32 msg)
>>> +{
>>> +    struct appletbdrm_msg_simple_request *request;
>>> +    int ret;
>>> +
>>> +    request = kzalloc(sizeof(*request), GFP_KERNEL);
>>> +    if (!request)
>>> +        return -ENOMEM;
>>> +
>>> +    request->header.unk_00 = cpu_to_le16(2);
>>> +    request->header.unk_02 = cpu_to_le16(0x1512);
>>> +    request->header.size = cpu_to_le32(sizeof(*request) - sizeof(request->header));
>>> +    request->msg = msg;
>>> +    request->size = request->header.size;
>>> +
>>> +    ret = appletbdrm_send_request(adev, &request->header, sizeof(*request));
>>> +
>>> +    kfree(request);
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +static int appletbdrm_clear_display(struct appletbdrm_device *adev)
>>> +{
>>> +    return appletbdrm_send_msg(adev, APPLETBDRM_MSG_CLEAR_DISPLAY);
>>> +}
>>> +
>>> +static int appletbdrm_signal_readiness(struct appletbdrm_device *adev)
>>> +{
>>> +    return appletbdrm_send_msg(adev, APPLETBDRM_MSG_SIGNAL_READINESS);
>>> +}
>>> +
>>> +static int appletbdrm_get_information(struct appletbdrm_device *adev)
>>> +{
>>> +    struct appletbdrm_msg_information *info;
>>> +    struct drm_device *drm = &adev->drm;
>>> +    u8 bits_per_pixel;
>>> +    __le32 pixel_format;
>>> +    int ret;
>>> +
>>> +    info = kzalloc(sizeof(*info), GFP_KERNEL);
>>> +    if (!info)
>>> +        return -ENOMEM;
>>> +
>>> +    ret = appletbdrm_send_msg(adev, APPLETBDRM_MSG_GET_INFORMATION);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    ret = appletbdrm_read_response(adev, &info->header, sizeof(*info),
>>> +                       APPLETBDRM_MSG_GET_INFORMATION);
>>> +    if (ret)
>>> +        goto free_info;
>>> +
>>> +    bits_per_pixel = info->bits_per_pixel;
>>> +    pixel_format = get_unaligned(&info->pixel_format);
>>> +
>>> +    adev->width = get_unaligned_le32(&info->width);
>>> +    adev->height = get_unaligned_le32(&info->height);
>>> +
>>> +    if (bits_per_pixel != APPLETBDRM_BITS_PER_PIXEL) {
>>> +        drm_err(drm, "Encountered unexpected bits per pixel value (%d)\n", bits_per_pixel);
>>> +        ret = -EINVAL;
>>> +        goto free_info;
>>> +    }
>>> +
>>> +    if (pixel_format != APPLETBDRM_PIXEL_FORMAT) {
>>> +        drm_err(drm, "Encountered unknown pixel format (%p4cc)\n", &pixel_format);
>>> +        ret = -EINVAL;
>>> +        goto free_info;
>>> +    }
>>> +
>>> +free_info:
>>> +    kfree(info);
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +static u32 rect_size(struct drm_rect *rect)
>>> +{
>>> +    return drm_rect_width(rect) * drm_rect_height(rect) *
>>> +        (BITS_TO_BYTES(APPLETBDRM_BITS_PER_PIXEL));
>>> +}
>>> +
>>> +static int appletbdrm_connector_helper_get_modes(struct drm_connector *connector)
>>> +{
>>> +    struct appletbdrm_device *adev = drm_to_adev(connector->dev);
>>> +
>>> +    return drm_connector_helper_get_modes_fixed(connector, &adev->mode);
>>> +}
>>> +
>>> +static const u32 appletbdrm_primary_plane_formats[] = {
>>> +    DRM_FORMAT_BGR888,
>>> +    DRM_FORMAT_XRGB8888, /* emulated */
>>> +};
>>> +
>>> +static int appletbdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
>>> +                           struct drm_atomic_state *state)
>>> +{
>>> +    struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state, plane);
>>> +    struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(state, plane);
>>> +    struct drm_crtc *new_crtc = new_plane_state->crtc;
>>> +    struct drm_crtc_state *new_crtc_state = NULL;
>>> +    struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(new_plane_state);
>>> +    struct drm_atomic_helper_damage_iter iter;
>>> +    struct drm_rect damage;
>>> +    size_t frames_size = 0;
>>> +    size_t request_size;
>>> +    int ret;
>>> +
>>> +    if (new_crtc)
>>> +        new_crtc_state = drm_atomic_get_new_crtc_state(state, new_crtc);
>>> +
>>> +    ret = drm_atomic_helper_check_plane_state(new_plane_state, new_crtc_state,
>>> +                          DRM_PLANE_NO_SCALING,
>>> +                          DRM_PLANE_NO_SCALING,
>>> +                          false, false);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    if (!new_plane_state->visible)
>>> +        return 0;
>>> +
>>> +    drm_atomic_helper_damage_iter_init(&iter, old_plane_state, new_plane_state);
>>> +    drm_atomic_for_each_plane_damage(&iter, &damage) {
>>> +        frames_size += struct_size((struct appletbdrm_frame *)0, buf, rect_size(&damage));
>>> +    }
>>> +
>>> +    if (!frames_size)
>>> +        return 0;
>>> +
>>> +    request_size = ALIGN(sizeof(struct appletbdrm_fb_request) +
>>> +               frames_size +
>>> +               sizeof(struct appletbdrm_fb_request_footer), 16);
>>> +
>>> +    appletbdrm_state->request = kzalloc(request_size, GFP_KERNEL);
>>> +
>>> +    if (!appletbdrm_state->request)
>>> +        return -ENOMEM;
>>> +
>>> +    appletbdrm_state->response = kzalloc(sizeof(*appletbdrm_state->response), GFP_KERNEL);
>>> +
>>> +    if (!appletbdrm_state->response)
>>> +        return -ENOMEM;
>>> +
>>> +    appletbdrm_state->request_size = request_size;
>>> +    appletbdrm_state->frames_size = frames_size;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int appletbdrm_flush_damage(struct appletbdrm_device *adev,
>>> +                   struct drm_plane_state *old_state,
>>> +                   struct drm_plane_state *state)
>>> +{
>>> +    struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state);
>>> +    struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
>>> +    struct appletbdrm_fb_request_response *response = appletbdrm_state->response;
>>> +    struct appletbdrm_fb_request_footer *footer;
>>> +    struct drm_atomic_helper_damage_iter iter;
>>> +    struct drm_framebuffer *fb = state->fb;
>>> +    struct appletbdrm_fb_request *request = appletbdrm_state->request;
>>> +    struct drm_device *drm = &adev->drm;
>>> +    struct appletbdrm_frame *frame;
>>> +    u64 timestamp = ktime_get_ns();
>>> +    struct drm_rect damage;
>>> +    size_t frames_size = appletbdrm_state->frames_size;
>>> +    size_t request_size = appletbdrm_state->request_size;
>>> +    int ret;
>>> +
>>> +    if (!frames_size)
>>> +        return 0;
>>> +
>>> +    ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to start CPU framebuffer access (%d)\n", ret);
>>> +        goto end_fb_cpu_access;
>>> +    }
>>> +
>>> +    request->header.unk_00 = cpu_to_le16(2);
>>> +    request->header.unk_02 = cpu_to_le16(0x12);
>>> +    request->header.unk_04 = cpu_to_le32(9);
>>> +    request->header.size = cpu_to_le32(request_size - sizeof(request->header));
>>> +    request->unk_10 = cpu_to_le16(1);
>>> +    request->msg_id = timestamp;
>>> +
>>> +    frame = (struct appletbdrm_frame *)request->data;
>>> +
>>> +    drm_atomic_helper_damage_iter_init(&iter, old_state, state);
>>> +    drm_atomic_for_each_plane_damage(&iter, &damage) {
>>> +        struct drm_rect dst_clip = state->dst;
>>> +        struct iosys_map dst = IOSYS_MAP_INIT_VADDR(frame->buf);
>>> +        u32 buf_size = rect_size(&damage);
>>> +
>>> +        if (!drm_rect_intersect(&dst_clip, &damage))
>>> +            continue;
>>> +
>>> +        /*
>>> +         * The coordinates need to be translated to the coordinate
>>> +         * system the device expects, see the comment in
>>> +         * appletbdrm_setup_mode_config
>>> +         */
>>> +        frame->begin_x = cpu_to_le16(damage.y1);
>>> +        frame->begin_y = cpu_to_le16(adev->height - damage.x2);
>>> +        frame->width = cpu_to_le16(drm_rect_height(&damage));
>>> +        frame->height = cpu_to_le16(drm_rect_width(&damage));
>>> +        frame->buf_size = cpu_to_le32(buf_size);
>>> +
>>> +        switch (fb->format->format) {
>>> +        case DRM_FORMAT_XRGB8888:
>>> +            drm_fb_xrgb8888_to_bgr888(&dst, NULL, &shadow_plane_state->data[0], fb, &damage, &shadow_plane_state->fmtcnv_state);
>>> +            break;
>>> +        default:
>>> +            drm_fb_memcpy(&dst, NULL, &shadow_plane_state->data[0], fb, &damage);
>>> +            break;
>>> +        }
>>> +
>>> +        frame = (void *)frame + struct_size(frame, buf, buf_size);
>>> +    }
>>> +
>>> +    footer = (struct appletbdrm_fb_request_footer *)&request->data[frames_size];
>>> +
>>> +    footer->unk_0c = cpu_to_le32(0xfffe);
>>> +    footer->unk_1c = cpu_to_le32(0x80001);
>>> +    footer->unk_34 = cpu_to_le32(0x80002);
>>> +    footer->unk_4c = cpu_to_le32(0xffff);
>>> +    footer->timestamp = cpu_to_le64(timestamp);
>>> +
>>> +    ret = appletbdrm_send_request(adev, &request->header, request_size);
>>> +    if (ret)
>>> +        goto end_fb_cpu_access;
>>> +
>>> +    ret = appletbdrm_read_response(adev, &response->header, sizeof(*response),
>>> +                       APPLETBDRM_MSG_UPDATE_COMPLETE);
>>> +    if (ret)
>>> +        goto end_fb_cpu_access;
>>> +
>>> +    if (response->timestamp != footer->timestamp) {
>>> +        drm_err(drm, "Response timestamp (%llu) doesn't match request timestamp (%llu)\n",
>>> +            le64_to_cpu(response->timestamp), timestamp);
>>> +        goto end_fb_cpu_access;
>>> +    }
>>> +
>>> +end_fb_cpu_access:
>>> +    drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +static void appletbdrm_primary_plane_helper_atomic_update(struct drm_plane *plane,
>>> +                             struct drm_atomic_state *old_state)
>>> +{
>>> +    struct appletbdrm_device *adev = drm_to_adev(plane->dev);
>>> +    struct drm_device *drm = plane->dev;
>>> +    struct drm_plane_state *plane_state = plane->state;
>>> +    struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(old_state, plane);
>>> +    int idx;
>>> +
>>> +    if (!drm_dev_enter(drm, &idx))
>>> +        return;
>>> +
>>> +    appletbdrm_flush_damage(adev, old_plane_state, plane_state);
>>> +
>>> +    drm_dev_exit(idx);
>>> +}
>>> +
>>> +static void appletbdrm_primary_plane_helper_atomic_disable(struct drm_plane *plane,
>>> +                               struct drm_atomic_state *state)
>>> +{
>>> +    struct drm_device *dev = plane->dev;
>>> +    struct appletbdrm_device *adev = drm_to_adev(dev);
>>> +    int idx;
>>> +
>>> +    if (!drm_dev_enter(dev, &idx))
>>> +        return;
>>> +
>>> +    appletbdrm_clear_display(adev);
>>> +
>>> +    drm_dev_exit(idx);
>>> +}
>>> +
>>> +static void appletbdrm_primary_plane_reset(struct drm_plane *plane)
>>> +{
>>> +    struct appletbdrm_plane_state *appletbdrm_state;
>>> +
>>> +    WARN_ON(plane->state);
>>> +
>>> +    appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL);
>>> +    if (!appletbdrm_state)
>>> +        return;
>>> +
>>> +    __drm_gem_reset_shadow_plane(plane, &appletbdrm_state->base);
>>> +}
>>> +
>>> +static struct drm_plane_state *appletbdrm_primary_plane_duplicate_state(struct drm_plane *plane)
>>> +{
>>> +    struct drm_shadow_plane_state *new_shadow_plane_state;
>>> +    struct appletbdrm_plane_state *old_appletbdrm_state;
>>> +    struct appletbdrm_plane_state *appletbdrm_state;
>>> +
>>> +    if (WARN_ON(!plane->state))
>>> +        return NULL;
>>> +
>>> +    old_appletbdrm_state = to_appletbdrm_plane_state(plane->state);
>>> +    appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL);
>>> +    if (!appletbdrm_state)
>>> +        return NULL;
>>> +
>>> +    /* Request and response are not duplicated and are allocated in .atomic_check */
>>> +    appletbdrm_state->request = NULL;
>>> +    appletbdrm_state->response = NULL;
>>> +
>>> +    appletbdrm_state->request_size = 0;
>>> +    appletbdrm_state->frames_size = 0;
>>> +
>>> +    new_shadow_plane_state = &appletbdrm_state->base;
>>> +
>>> +    __drm_gem_duplicate_shadow_plane_state(plane, new_shadow_plane_state);
>>> +
>>> +    return &new_shadow_plane_state->base;
>>> +}
>>> +
>>> +static void appletbdrm_primary_plane_destroy_state(struct drm_plane *plane,
>>> +                           struct drm_plane_state *state)
>>> +{
>>> +    struct appletbdrm_plane_state *appletbdrm_state = to_appletbdrm_plane_state(state);
>>> +
>>> +    kfree(appletbdrm_state->request);
>>> +    kfree(appletbdrm_state->response);
>>> +
>>> +    __drm_gem_destroy_shadow_plane_state(&appletbdrm_state->base);
>>> +
>>> +    kfree(appletbdrm_state);
>>> +}
>>> +
>>> +static const struct drm_plane_helper_funcs appletbdrm_primary_plane_helper_funcs = {
>>> +    DRM_GEM_SHADOW_PLANE_HELPER_FUNCS,
>>> +    .atomic_check = appletbdrm_primary_plane_helper_atomic_check,
>>> +    .atomic_update = appletbdrm_primary_plane_helper_atomic_update,
>>> +    .atomic_disable = appletbdrm_primary_plane_helper_atomic_disable,
>>> +};
>>> +
>>> +static const struct drm_plane_funcs appletbdrm_primary_plane_funcs = {
>>> +    .update_plane = drm_atomic_helper_update_plane,
>>> +    .disable_plane = drm_atomic_helper_disable_plane,
>>> +    .reset = appletbdrm_primary_plane_reset,
>>> +    .atomic_duplicate_state = appletbdrm_primary_plane_duplicate_state,
>>> +    .atomic_destroy_state = appletbdrm_primary_plane_destroy_state,
>>> +    .destroy = drm_plane_cleanup,
>>> +};
>>> +
>>> +static enum drm_mode_status appletbdrm_crtc_helper_mode_valid(struct drm_crtc *crtc,
>>> +                              const struct drm_display_mode *mode)
>>> +{
>>> +    struct appletbdrm_device *adev = drm_to_adev(crtc->dev);
>>> +
>>> +    return drm_crtc_helper_mode_valid_fixed(crtc, mode, &adev->mode);
>>> +}
>>> +
>>> +static const struct drm_mode_config_funcs appletbdrm_mode_config_funcs = {
>>> +    .fb_create = drm_gem_fb_create_with_dirty,
>>> +    .atomic_check = drm_atomic_helper_check,
>>> +    .atomic_commit = drm_atomic_helper_commit,
>>> +};
>>> +
>>> +static const struct drm_connector_funcs appletbdrm_connector_funcs = {
>>> +    .reset = drm_atomic_helper_connector_reset,
>>> +    .destroy = drm_connector_cleanup,
>>> +    .fill_modes = drm_helper_probe_single_connector_modes,
>>> +    .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
>>> +    .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
>>> +};
>>> +
>>> +static const struct drm_connector_helper_funcs appletbdrm_connector_helper_funcs = {
>>> +    .get_modes = appletbdrm_connector_helper_get_modes,
>>> +};
>>> +
>>> +static const struct drm_crtc_helper_funcs appletbdrm_crtc_helper_funcs = {
>>> +    .mode_valid = appletbdrm_crtc_helper_mode_valid,
>>> +};
>>> +
>>> +static const struct drm_crtc_funcs appletbdrm_crtc_funcs = {
>>> +    .reset = drm_atomic_helper_crtc_reset,
>>> +    .destroy = drm_crtc_cleanup,
>>> +    .set_config = drm_atomic_helper_set_config,
>>> +    .page_flip = drm_atomic_helper_page_flip,
>>> +    .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
>>> +    .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
>>> +};
>>> +
>>> +static const struct drm_encoder_funcs appletbdrm_encoder_funcs = {
>>> +    .destroy = drm_encoder_cleanup,
>>> +};
>>> +
>>> +static struct drm_gem_object *appletbdrm_driver_gem_prime_import(struct drm_device *dev,
>>> +                                 struct dma_buf *dma_buf)
>>> +{
>>> +    struct appletbdrm_device *adev = drm_to_adev(dev);
>>> +
>>> +    if (!adev->dev)
>>> +        return ERR_PTR(-ENODEV);
>>> +
>>> +    return drm_gem_prime_import_dev(dev, dma_buf, adev->dev);
>>> +}
>>> +
>>> +DEFINE_DRM_GEM_FOPS(appletbdrm_drm_fops);
>>> +
>>> +static const struct drm_driver appletbdrm_drm_driver = {
>>> +    DRM_GEM_SHMEM_DRIVER_OPS,
>>> +    .gem_prime_import    = appletbdrm_driver_gem_prime_import,
>>> +    .name            = "appletbdrm",
>>> +    .desc            = "Apple Touch Bar DRM Driver",
>>> +    .major            = 1,
>>> +    .minor            = 0,
>>> +    .driver_features    = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
>>> +    .fops            = &appletbdrm_drm_fops,
>>> +};
>>> +
>>> +static int appletbdrm_setup_mode_config(struct appletbdrm_device *adev)
>>> +{
>>> +    struct drm_connector *connector = &adev->connector;
>>> +    struct drm_plane *primary_plane;
>>> +    struct drm_crtc *crtc;
>>> +    struct drm_encoder *encoder;
>>> +    struct drm_device *drm = &adev->drm;
>>> +    int ret;
>>> +
>>> +    ret = drmm_mode_config_init(drm);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to initialize mode configuration\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    primary_plane = &adev->primary_plane;
>>> +    ret = drm_universal_plane_init(drm, primary_plane, 0,
>>> +                       &appletbdrm_primary_plane_funcs,
>>> +                       appletbdrm_primary_plane_formats,
>>> +                       ARRAY_SIZE(appletbdrm_primary_plane_formats),
>>> +                       NULL,
>>> +                       DRM_PLANE_TYPE_PRIMARY, NULL);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to initialize universal plane object\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    drm_plane_helper_add(primary_plane, &appletbdrm_primary_plane_helper_funcs);
>>> +    drm_plane_enable_fb_damage_clips(primary_plane);
>>> +
>>> +    crtc = &adev->crtc;
>>> +    ret = drm_crtc_init_with_planes(drm, crtc, primary_plane, NULL,
>>> +                    &appletbdrm_crtc_funcs, NULL);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to initialize CRTC object\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    drm_crtc_helper_add(crtc, &appletbdrm_crtc_helper_funcs);
>>> +
>>> +    encoder = &adev->encoder;
>>> +    ret = drm_encoder_init(drm, encoder, &appletbdrm_encoder_funcs,
>>> +                   DRM_MODE_ENCODER_DAC, NULL);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to initialize encoder\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    encoder->possible_crtcs = drm_crtc_mask(crtc);
>>> +
>>> +    /*
>>> +     * The coordinate system used by the device is different from the
>>> +     * coordinate system of the framebuffer in that the x and y axes are
>>> +     * swapped, and that the y axis is inverted; so what the device reports
>>> +     * as the height is actually the width of the framebuffer and vice
>>> +     * versa
>>> +     */
>>> +    drm->mode_config.max_width = max(adev->height, DRM_SHADOW_PLANE_MAX_WIDTH);
>>> +    drm->mode_config.max_height = max(adev->width, DRM_SHADOW_PLANE_MAX_HEIGHT);
>>> +    drm->mode_config.preferred_depth = APPLETBDRM_BITS_PER_PIXEL;
>>> +    drm->mode_config.funcs = &appletbdrm_mode_config_funcs;
>>> +
>>> +    adev->mode = (struct drm_display_mode) {
>>> +        DRM_MODE_INIT(60, adev->height, adev->width,
>>> +                  DRM_MODE_RES_MM(adev->height, 218),
>>> +                  DRM_MODE_RES_MM(adev->width, 218))
>>> +    };
>>> +
>>> +    ret = drm_connector_init(drm, connector,
>>> +                 &appletbdrm_connector_funcs, DRM_MODE_CONNECTOR_USB);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to initialize connector\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    drm_connector_helper_add(connector, &appletbdrm_connector_helper_funcs);
>>> +
>>> +    ret = drm_connector_set_panel_orientation(connector,
>>> +                          DRM_MODE_PANEL_ORIENTATION_RIGHT_UP);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to set panel orientation\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    connector->display_info.non_desktop = true;
>>> +    ret = drm_object_property_set_value(&connector->base,
>>> +                        drm->mode_config.non_desktop_property, true);
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to set non-desktop property\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    ret = drm_connector_attach_encoder(connector, encoder);
>>> +
>>> +    if (ret) {
>>> +        drm_err(drm, "Failed to initialize simple display pipe\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    drm_mode_config_reset(drm);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int appletbdrm_probe(struct usb_interface *intf,
>>> +                const struct usb_device_id *id)
>>> +{
>>> +    struct usb_endpoint_descriptor *bulk_in, *bulk_out;
>>> +    struct device *dev = &intf->dev;
>>> +    struct appletbdrm_device *adev;
>>> +    struct drm_device *drm;
>>> +    int ret;
>>> +
>>> +    ret = usb_find_common_endpoints(intf->cur_altsetting, &bulk_in, &bulk_out, NULL, NULL);
>>> +    if (ret)
>>> +        return dev_err_probe(dev, ret, "Failed to find bulk endpoints\n");
>>> +
>>> +    adev = devm_drm_dev_alloc(dev, &appletbdrm_drm_driver, struct appletbdrm_device, drm);
>>> +    if (IS_ERR(adev))
>>> +        return PTR_ERR(adev);
>>> +
>>> +    adev->dev = dev;
>>> +    adev->in_ep = bulk_in->bEndpointAddress;
>>> +    adev->out_ep = bulk_out->bEndpointAddress;
>>> +
>>> +    drm = &adev->drm;
>>> +
>>> +    usb_set_intfdata(intf, adev);
>>> +
>>> +    ret = appletbdrm_get_information(adev);
>>> +    if (ret)
>>> +        return dev_err_probe(dev, ret, "Failed to get display information\n");
>>> +
>>> +    ret = appletbdrm_signal_readiness(adev);
>>> +    if (ret)
>>> +        return dev_err_probe(dev, ret, "Failed to signal readiness\n");
>>> +
>>> +    ret = appletbdrm_setup_mode_config(adev);
>>> +    if (ret)
>>> +        return dev_err_probe(dev, ret, "Failed to setup mode config\n");
>>> +
>>> +    ret = drm_dev_register(drm, 0);
>>> +    if (ret)
>>> +        return dev_err_probe(dev, ret, "Failed to register DRM device\n");
>>> +
>>> +    ret = appletbdrm_clear_display(adev);
>>> +    if (ret)
>>> +        return dev_err_probe(dev, ret, "Failed to clear display\n");
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static void appletbdrm_disconnect(struct usb_interface *intf)
>>> +{
>>> +    struct appletbdrm_device *adev = usb_get_intfdata(intf);
>>> +    struct drm_device *drm = &adev->drm;
>>> +
>>> +    put_device(adev->dev);
>>> +    drm_dev_unplug(drm);
>>> +    drm_atomic_helper_shutdown(drm);
>>> +}
>>> +
>>> +static void appletbdrm_shutdown(struct usb_interface *intf)
>>> +{
>>> +    struct appletbdrm_device *adev = usb_get_intfdata(intf);
>>> +
>>> +    /*
>>> +     * The framebuffer needs to be cleared on shutdown since its content
>>> +     * persists across boots
>>> +     */
>>> +    drm_atomic_helper_shutdown(&adev->drm);
>>> +}
>>> +
>>> +static const struct usb_device_id appletbdrm_usb_id_table[] = {
>>> +    { USB_DEVICE_INTERFACE_CLASS(0x05ac, 0x8302, USB_CLASS_AUDIO_VIDEO) },
>>> +    {}
>>> +};
>>> +MODULE_DEVICE_TABLE(usb, appletbdrm_usb_id_table);
>>> +
>>> +static struct usb_driver appletbdrm_usb_driver = {
>>> +    .name        = "appletbdrm",
>>> +    .probe        = appletbdrm_probe,
>>> +    .disconnect    = appletbdrm_disconnect,
>>> +    .shutdown    = appletbdrm_shutdown,
>>> +    .id_table    = appletbdrm_usb_id_table,
>>> +};
>>> +module_usb_driver(appletbdrm_usb_driver);
>>> +
>>> +MODULE_AUTHOR("Kerem Karabay <kekrby@gmail.com>");
>>> +MODULE_DESCRIPTION("Apple Touch Bar DRM Driver");
>>> +MODULE_LICENSE("GPL");
>> --
>> --
>> Thomas Zimmermann
>> Graphics Driver Developer
>> SUSE Software Solutions Germany GmbH
>> Frankenstrasse 146, 90461 Nuernberg, Germany
>> GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
>> HRB 36809 (AG Nuernberg)
>>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Tue, Feb 25, 2025 at 09:48:11AM +0100, Thomas Zimmermann wrote:
> Am 25.02.25 um 09:00 schrieb Aditya Garg:
> > > On 25 Feb 2025, at 1:22 PM, Thomas Zimmermann <tzimmermann@suse.de> wrote:
> > > > Am 24.02.25 um 14:40 schrieb Aditya Garg:

...

> > > > +struct appletbdrm_device {
> > > > +    struct device *dev;
> > > This field should go away, please. There's drm.dev, which contains the same address.
> > > 
> > > So seems to have remove the dmadev field instead, which you'll need for
> > > dma-buf sharing. Was that a misunderstanding from the last review?
> > Yeah that was a misunderstanding. I though you meant to remove dmadev.
> > > The rest of the driver looks good.
> > Maybe you missed the left over dev_err_probe left in this patch? I'll fix
> > them.
> 
> Sure.

But can you comment on my reply where I'm asking for a clarification how
drm_err() can be used on the physical device ->probe() to begin with?

> > > > +    unsigned int in_ep;
> > > > +    unsigned int out_ep;
> > > > +
> > > > +    unsigned int width;
> > > > +    unsigned int height;
> > > > +
> > > > +    struct drm_device drm;
> > > > +    struct drm_display_mode mode;
> > > > +    struct drm_connector connector;
> > > > +    struct drm_plane primary_plane;
> > > > +    struct drm_crtc crtc;
> > > > +    struct drm_encoder encoder;
> > > > +};

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[kernel test robot]

Hi Aditya,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.14-rc4 next-20250227]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Aditya-Garg/drm-format-helper-Add-conversion-from-XRGB8888-to-BGR888/20250224-214352
base:   linus/master
patch link:    https://lore.kernel.org/r/844C1D39-4891-4DC2-8458-F46FA1B59FA0%40live.com
patch subject: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs
config: alpha-kismet-CONFIG_HID_MULTITOUCH-CONFIG_DRM_APPLETBDRM-0-0 (https://download.01.org/0day-ci/archive/20250228/202502280028.1Y9QMcR0-lkp@intel.com/config)
reproduce: (https://download.01.org/0day-ci/archive/20250228/202502280028.1Y9QMcR0-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202502280028.1Y9QMcR0-lkp@intel.com/

kismet warnings: (new ones prefixed by >>)
>> kismet: WARNING: unmet direct dependencies detected for HID_MULTITOUCH when selected by DRM_APPLETBDRM
   WARNING: unmet direct dependencies detected for HID_MULTITOUCH
     Depends on [n]: HID_SUPPORT [=n] && HID [=n]
     Selected by [y]:
     - DRM_APPLETBDRM [=y] && HAS_IOMEM [=y] && DRM [=y] && USB [=y] && MMU [=y]

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[Aditya Garg]

> On 27 Feb 2025, at 10:24 PM, kernel test robot <lkp@intel.com> wrote:
> 
> Hi Aditya,
> 
> kernel test robot noticed the following build warnings:
> 
> [auto build test WARNING on linus/master]
> [also build test WARNING on v6.14-rc4 next-20250227]
> [If your patch is applied to the wrong git tree, kindly drop us a note.

A version 7 of this patch has already been submitted, not sure why kernel test robot tested version 4

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[andriy.shevchenko]

On Thu, Feb 27, 2025 at 05:28:33PM +0000, Aditya Garg wrote:
> > On 27 Feb 2025, at 10:24 PM, kernel test robot <lkp@intel.com> wrote:
> > Hi Aditya,
> > 
> > kernel test robot noticed the following build warnings:
> > 
> > [auto build test WARNING on linus/master]
> > [also build test WARNING on v6.14-rc4 next-20250227]
> > [If your patch is applied to the wrong git tree, kindly drop us a note.
> 
> A version 7 of this patch has already been submitted, not sure why kernel test robot tested version 4

Because you are too fast to send a new versions. Whenever patch appears in ML
it is seconds/minutes to trigger a bot build, which takes hours. I recommend
spend more time on thinking and discussing, than issuing versions like from
a machine gun.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[kernel test robot]

Hi Aditya,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.14-rc4 next-20250227]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Aditya-Garg/drm-format-helper-Add-conversion-from-XRGB8888-to-BGR888/20250224-214352
base:   linus/master
patch link:    https://lore.kernel.org/r/844C1D39-4891-4DC2-8458-F46FA1B59FA0%40live.com
patch subject: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs
config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20250228/202502280740.4ffoKiLx-lkp@intel.com/config)
compiler: mips-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250228/202502280740.4ffoKiLx-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202502280740.4ffoKiLx-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/gpu/drm/tiny/appletbdrm.c:13:
   drivers/gpu/drm/tiny/appletbdrm.c: In function 'appletbdrm_send_request':
>> include/drm/drm_print.h:589:54: warning: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type 'size_t' {aka 'unsigned int'} [-Wformat=]
     589 |         dev_##level##type((drm) ? (drm)->dev : NULL, "[drm] " fmt, ##__VA_ARGS__)
         |                                                      ^~~~~~~~
   include/linux/dev_printk.h:110:30: note: in definition of macro 'dev_printk_index_wrap'
     110 |                 _p_func(dev, fmt, ##__VA_ARGS__);                       \
         |                              ^~~
   include/linux/dev_printk.h:154:56: note: in expansion of macro 'dev_fmt'
     154 |         dev_printk_index_wrap(_dev_err, KERN_ERR, dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                                                        ^~~~~~~
   include/drm/drm_print.h:589:9: note: in expansion of macro 'dev_err'
     589 |         dev_##level##type((drm) ? (drm)->dev : NULL, "[drm] " fmt, ##__VA_ARGS__)
         |         ^~~~
   include/drm/drm_print.h:602:9: note: in expansion of macro '__drm_printk'
     602 |         __drm_printk((drm), err,, "*ERROR* " fmt, ##__VA_ARGS__)
         |         ^~~~~~~~~~~~
   drivers/gpu/drm/tiny/appletbdrm.c:173:17: note: in expansion of macro 'drm_err'
     173 |                 drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
         |                 ^~~~~~~
   drivers/gpu/drm/tiny/appletbdrm.c: In function 'appletbdrm_read_response':
>> include/drm/drm_print.h:589:54: warning: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type 'size_t' {aka 'unsigned int'} [-Wformat=]
     589 |         dev_##level##type((drm) ? (drm)->dev : NULL, "[drm] " fmt, ##__VA_ARGS__)
         |                                                      ^~~~~~~~
   include/linux/dev_printk.h:110:30: note: in definition of macro 'dev_printk_index_wrap'
     110 |                 _p_func(dev, fmt, ##__VA_ARGS__);                       \
         |                              ^~~
   include/linux/dev_printk.h:154:56: note: in expansion of macro 'dev_fmt'
     154 |         dev_printk_index_wrap(_dev_err, KERN_ERR, dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                                                        ^~~~~~~
   include/drm/drm_print.h:589:9: note: in expansion of macro 'dev_err'
     589 |         dev_##level##type((drm) ? (drm)->dev : NULL, "[drm] " fmt, ##__VA_ARGS__)
         |         ^~~~
   include/drm/drm_print.h:602:9: note: in expansion of macro '__drm_printk'
     602 |         __drm_printk((drm), err,, "*ERROR* " fmt, ##__VA_ARGS__)
         |         ^~~~~~~~~~~~
   drivers/gpu/drm/tiny/appletbdrm.c:214:17: note: in expansion of macro 'drm_err'
     214 |                 drm_err(drm, "Actual size (%d) doesn't match expected size (%lu)\n",
         |                 ^~~~~~~
   drivers/gpu/drm/tiny/appletbdrm.c: In function 'appletbdrm_primary_plane_duplicate_state':
   drivers/gpu/drm/tiny/appletbdrm.c:524:40: warning: variable 'old_appletbdrm_state' set but not used [-Wunused-but-set-variable]
     524 |         struct appletbdrm_plane_state *old_appletbdrm_state;
         |                                        ^~~~~~~~~~~~~~~~~~~~


vim +589 include/drm/drm_print.h

e820f52577b14c6 Jim Cromie            2022-09-11  549  
02c9656b2f0d699 Haneen Mohammed       2017-10-17  550  /**
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  551   * DRM_DEV_DEBUG() - Debug output for generic drm code
02c9656b2f0d699 Haneen Mohammed       2017-10-17  552   *
306589856399e18 Douglas Anderson      2021-09-21  553   * NOTE: this is deprecated in favor of drm_dbg_core().
306589856399e18 Douglas Anderson      2021-09-21  554   *
091756bbb1a9613 Haneen Mohammed       2017-10-17  555   * @dev: device pointer
091756bbb1a9613 Haneen Mohammed       2017-10-17  556   * @fmt: printf() like format string.
02c9656b2f0d699 Haneen Mohammed       2017-10-17  557   */
db87086492581c8 Joe Perches           2018-03-16  558  #define DRM_DEV_DEBUG(dev, fmt, ...)					\
db87086492581c8 Joe Perches           2018-03-16  559  	drm_dev_dbg(dev, DRM_UT_CORE, fmt, ##__VA_ARGS__)
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  560  /**
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  561   * DRM_DEV_DEBUG_DRIVER() - Debug output for vendor specific part of the driver
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  562   *
306589856399e18 Douglas Anderson      2021-09-21  563   * NOTE: this is deprecated in favor of drm_dbg() or dev_dbg().
306589856399e18 Douglas Anderson      2021-09-21  564   *
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  565   * @dev: device pointer
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  566   * @fmt: printf() like format string.
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  567   */
db87086492581c8 Joe Perches           2018-03-16  568  #define DRM_DEV_DEBUG_DRIVER(dev, fmt, ...)				\
db87086492581c8 Joe Perches           2018-03-16  569  	drm_dev_dbg(dev, DRM_UT_DRIVER,	fmt, ##__VA_ARGS__)
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  570  /**
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  571   * DRM_DEV_DEBUG_KMS() - Debug output for modesetting code
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  572   *
306589856399e18 Douglas Anderson      2021-09-21  573   * NOTE: this is deprecated in favor of drm_dbg_kms().
306589856399e18 Douglas Anderson      2021-09-21  574   *
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  575   * @dev: device pointer
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  576   * @fmt: printf() like format string.
b52817e9de06a3a Mauro Carvalho Chehab 2020-10-27  577   */
db87086492581c8 Joe Perches           2018-03-16  578  #define DRM_DEV_DEBUG_KMS(dev, fmt, ...)				\
db87086492581c8 Joe Perches           2018-03-16  579  	drm_dev_dbg(dev, DRM_UT_KMS, fmt, ##__VA_ARGS__)
a18b21929453af7 Lyude Paul            2018-07-16  580  
fb6c7ab8718eb25 Jani Nikula           2019-12-10  581  /*
fb6c7ab8718eb25 Jani Nikula           2019-12-10  582   * struct drm_device based logging
fb6c7ab8718eb25 Jani Nikula           2019-12-10  583   *
fb6c7ab8718eb25 Jani Nikula           2019-12-10  584   * Prefer drm_device based logging over device or prink based logging.
fb6c7ab8718eb25 Jani Nikula           2019-12-10  585   */
fb6c7ab8718eb25 Jani Nikula           2019-12-10  586  
fb6c7ab8718eb25 Jani Nikula           2019-12-10  587  /* Helper for struct drm_device based logging. */
fb6c7ab8718eb25 Jani Nikula           2019-12-10  588  #define __drm_printk(drm, level, type, fmt, ...)			\
e04d24c4e8062b5 Luben Tuikov          2023-11-16 @589  	dev_##level##type((drm) ? (drm)->dev : NULL, "[drm] " fmt, ##__VA_ARGS__)
fb6c7ab8718eb25 Jani Nikula           2019-12-10  590  
fb6c7ab8718eb25 Jani Nikula           2019-12-10  591  

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Re: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs

[kernel test robot]

Hi Aditya,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.14-rc4 next-20250227]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Aditya-Garg/drm-format-helper-Add-conversion-from-XRGB8888-to-BGR888/20250224-214352
base:   linus/master
patch link:    https://lore.kernel.org/r/844C1D39-4891-4DC2-8458-F46FA1B59FA0%40live.com
patch subject: [PATCH v4 2/2] drm/tiny: add driver for Apple Touch Bars in x86 Macs
config: loongarch-allyesconfig (https://download.01.org/0day-ci/archive/20250228/202502280748.oNKTNuMK-lkp@intel.com/config)
compiler: loongarch64-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250228/202502280748.oNKTNuMK-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202502280748.oNKTNuMK-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/gpu/drm/tiny/appletbdrm.c: In function 'appletbdrm_primary_plane_duplicate_state':
>> drivers/gpu/drm/tiny/appletbdrm.c:524:40: warning: variable 'old_appletbdrm_state' set but not used [-Wunused-but-set-variable]
     524 |         struct appletbdrm_plane_state *old_appletbdrm_state;
         |                                        ^~~~~~~~~~~~~~~~~~~~


vim +/old_appletbdrm_state +524 drivers/gpu/drm/tiny/appletbdrm.c

   520	
   521	static struct drm_plane_state *appletbdrm_primary_plane_duplicate_state(struct drm_plane *plane)
   522	{
   523		struct drm_shadow_plane_state *new_shadow_plane_state;
 > 524		struct appletbdrm_plane_state *old_appletbdrm_state;
   525		struct appletbdrm_plane_state *appletbdrm_state;
   526	
   527		if (WARN_ON(!plane->state))
   528			return NULL;
   529	
   530		old_appletbdrm_state = to_appletbdrm_plane_state(plane->state);
   531		appletbdrm_state = kzalloc(sizeof(*appletbdrm_state), GFP_KERNEL);
   532		if (!appletbdrm_state)
   533			return NULL;
   534	
   535		/* Request and response are not duplicated and are allocated in .atomic_check */
   536		appletbdrm_state->request = NULL;
   537		appletbdrm_state->response = NULL;
   538	
   539		appletbdrm_state->request_size = 0;
   540		appletbdrm_state->frames_size = 0;
   541	
   542		new_shadow_plane_state = &appletbdrm_state->base;
   543	
   544		__drm_gem_duplicate_shadow_plane_state(plane, new_shadow_plane_state);
   545	
   546		return &new_shadow_plane_state->base;
   547	}
   548	

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