Re: [meta-raspberrypi][PATCH 4/5] linux-raspberrypi: Add a 4.1 linux kernel with vc4 support

[Andrei Gherzan <andrei@gherzan.ro>]

Hi,

On Thu, Jul 30, 2015 at 10:34:10AM +0200, Javier Martinez Canillas wrote:
> From: Derek Foreman <derekf@osg.samsung.com>
>
> This adds Eric Anholt's WIP kernel with dri/kms/3d support for the GPU on
> the rpi2. Adding a recipe that tracks this kernel, will make it easier to
> test this setup.
>
> This recipe should only used for testing purposes for now, so it will not
> be set as the default.
>
> The kernel will be choosen though if the "vc4-gfx" feature has been added
> to the the DISTRO_FEATURES variable.
>

It was said before - it seems like this is a MACHINE_FEATURE. I know you will
address this in V2.

> Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
> [javier: Extended commit message and set default preference to -1]
> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
>
> ---
>
>  README                                             |   9 ++

Please split this change in another patch.

>  ..._defconfig-Enable-config-options-for-vc4-.patch |  48 +++++++++
>  ...-ARM-dts-Fix-i2c-for-bcm2709-RPI2-B-board.patch |  85 +++++++++++++++
>  .../0003-drm-vc4-Use-the-fbdev_cma-helpers.patch   | 115 +++++++++++++++++++++
>  .../0004-drm-vc4-Allow-vblank-to-be-disabled.patch |  26 +++++
>  .../0005-drm-vc4-Disable-KMS-operations.patch      |  95 +++++++++++++++++
>  recipes-kernel/linux/linux-raspberrypi_4.1.bb      |  16 +++
>  7 files changed, 394 insertions(+)
>  create mode 100644 recipes-kernel/linux/linux-raspberrypi/0001-ARM-bcm2709_defconfig-Enable-config-options-for-vc4-.patch
>  create mode 100644 recipes-kernel/linux/linux-raspberrypi/0002-ARM-dts-Fix-i2c-for-bcm2709-RPI2-B-board.patch
>  create mode 100644 recipes-kernel/linux/linux-raspberrypi/0003-drm-vc4-Use-the-fbdev_cma-helpers.patch
>  create mode 100644 recipes-kernel/linux/linux-raspberrypi/0004-drm-vc4-Allow-vblank-to-be-disabled.patch
>  create mode 100644 recipes-kernel/linux/linux-raspberrypi/0005-drm-vc4-Disable-KMS-operations.patch
>  create mode 100644 recipes-kernel/linux/linux-raspberrypi_4.1.bb
>
> diff --git a/README b/README
> index 678c0eb4a4e3..20788d6f48cb 100644
> --- a/README
> +++ b/README
> @@ -25,6 +25,7 @@ Contents:
>      2.K. Boot to U-Boot
>      2.L. Image with Initramfs
>      2.M. Device tree support
> +    2.O. Graphics stack
>  3. Extra apps
>      3.A. omxplayer
>  4. Source code and mirrors
> @@ -195,6 +196,14 @@ kernels.
>  NOTE: KERNEL_DEVICETREE is default enabled for kernel >= 3.18 and always disabled for
>        older kernel versions.
>
> +2.O. Graphic stacks
> +===================
> +The Raspberry Pi boards can use one of two graphics stacks: The userland
> +user-space driver or the vc4 DRM/KMS kernel driver. By default userland
> +is used since the vc4 is still experimental. But this can be changed by
> +setting the following in the local.conf
> +DISTRO_FEATURES_append = " vc4-gfx"

Userland / binaries : vc-*. I'm wondering if we should actually define a
feature for this or just let the users configure the providers as they want. We
do this for vc-* / userland. We don't have a feature to switch from binaries to
userland or so.

> +
>  3. Extra apps
>  =============
>
> diff --git a/recipes-kernel/linux/linux-raspberrypi/0001-ARM-bcm2709_defconfig-Enable-config-options-for-vc4-.patch b/recipes-kernel/linux/linux-raspberrypi/0001-ARM-bcm2709_defconfig-Enable-config-options-for-vc4-.patch
> new file mode 100644
> index 000000000000..1ea62489e077
> --- /dev/null
> +++ b/recipes-kernel/linux/linux-raspberrypi/0001-ARM-bcm2709_defconfig-Enable-config-options-for-vc4-.patch
> @@ -0,0 +1,48 @@
> +From 5908700d3cb88114002aa66f920e91961ebe91e4 Mon Sep 17 00:00:00 2001
> +From: Derek Foreman <derekf@osg.samsung.com>
> +Date: Fri, 24 Jul 2015 01:58:31 +0200
> +Subject: [PATCH 1/5] ARM: bcm2709_defconfig: Enable config options for vc4
> + support
> +
> +Add the needed Kconfig symbols to build Eric Anholt's WIP kernel
> +4.1 Linux kernel with vc4 dri/kms/3d support. Also increase CMA
> +size from 5 MiB to 256 MiB as that is needed by the driver.
> +
> +Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
> +---
> + arch/arm/configs/bcm2709_defconfig | 5 ++++-
> + 1 file changed, 4 insertions(+), 1 deletion(-)
> +
> +diff --git a/arch/arm/configs/bcm2709_defconfig b/arch/arm/configs/bcm2709_defconfig
> +index a3067bfb610f..7891bb17df57 100644
> +--- a/arch/arm/configs/bcm2709_defconfig
> ++++ b/arch/arm/configs/bcm2709_defconfig
> +@@ -39,6 +39,7 @@ CONFIG_MAC_PARTITION=y
> + CONFIG_CFQ_GROUP_IOSCHED=y
> + CONFIG_ARCH_BCM2709=y
> + CONFIG_BCM2709_DT=y
> ++# CONFIG_VDSO is not set
> + # CONFIG_CACHE_L2X0 is not set
> + CONFIG_SMP=y
> + CONFIG_HAVE_ARM_ARCH_TIMER=y
> +@@ -388,7 +389,7 @@ CONFIG_NFC_PN533=m
> + CONFIG_DEVTMPFS=y
> + CONFIG_DEVTMPFS_MOUNT=y
> + CONFIG_DMA_CMA=y
> +-CONFIG_CMA_SIZE_MBYTES=5
> ++CONFIG_CMA_SIZE_MBYTES=256
> + CONFIG_BLK_DEV_LOOP=y
> + CONFIG_BLK_DEV_CRYPTOLOOP=m
> + CONFIG_BLK_DEV_DRBD=m
> +@@ -771,6 +772,8 @@ CONFIG_VIDEO_TW9906=m
> + CONFIG_VIDEO_OV7640=m
> + CONFIG_VIDEO_MT9V011=m
> + CONFIG_FB=y
> ++CONFIG_DRM=y
> ++CONFIG_DRM_VC4=y
> + CONFIG_FB_BCM2708=y
> + CONFIG_FB_SSD1307=m
> + # CONFIG_BACKLIGHT_GENERIC is not set
> +--
> +2.4.3
> +
> diff --git a/recipes-kernel/linux/linux-raspberrypi/0002-ARM-dts-Fix-i2c-for-bcm2709-RPI2-B-board.patch b/recipes-kernel/linux/linux-raspberrypi/0002-ARM-dts-Fix-i2c-for-bcm2709-RPI2-B-board.patch
> new file mode 100644
> index 000000000000..acc09760e820
> --- /dev/null
> +++ b/recipes-kernel/linux/linux-raspberrypi/0002-ARM-dts-Fix-i2c-for-bcm2709-RPI2-B-board.patch
> @@ -0,0 +1,85 @@
> +From 8882728be24f35f81da4558c84fb18658e23fcc9 Mon Sep 17 00:00:00 2001
> +From: Derek Foreman <derekf@osg.samsung.com>
> +Date: Wed, 27 May 2015 13:20:21 -0500
> +Subject: [PATCH 2/5] ARM: dts: Fix i2c for bcm2709 RPI2 B board
> +
> +Fix up device tree and i2c setup for rpi2
> +
> +Signed-off-by: Derek Foreman <derekf@osg.samsung.com
> +---
> + arch/arm/boot/dts/bcm2708_common.dtsi | 2 +-
> + arch/arm/boot/dts/bcm2709-rpi-2-b.dts | 6 ++++++
> + drivers/i2c/busses/i2c-bcm2708.c      | 6 +++++-
> + 3 files changed, 12 insertions(+), 2 deletions(-)
> +
> +diff --git a/arch/arm/boot/dts/bcm2708_common.dtsi b/arch/arm/boot/dts/bcm2708_common.dtsi
> +index ccf01a568cb6..15277d2765bb 100644
> +--- a/arch/arm/boot/dts/bcm2708_common.dtsi
> ++++ b/arch/arm/boot/dts/bcm2708_common.dtsi
> +@@ -155,7 +155,7 @@
> + 		};
> +
> + 		i2c2: i2c@7e805000 {
> +-			compatible = "brcm,bcm2835-i2c";
> ++			compatible = "brcm,bcm2708-i2c";
> + 			reg = <0x7e805000 0x1000>;
> + 			interrupts = <2 21>;
> + 			clocks = <&clk_i2c>;
> +diff --git a/arch/arm/boot/dts/bcm2709-rpi-2-b.dts b/arch/arm/boot/dts/bcm2709-rpi-2-b.dts
> +index 8aaaf1fb7143..712ca455cc46 100644
> +--- a/arch/arm/boot/dts/bcm2709-rpi-2-b.dts
> ++++ b/arch/arm/boot/dts/bcm2709-rpi-2-b.dts
> +@@ -11,6 +11,7 @@
> + 		spi0 = &spi0;
> + 		i2c0 = &i2c0;
> + 		i2c1 = &i2c1;
> ++		i2c2 = &i2c2;
> + 		i2s  = &i2s;
> + 		gpio = &gpio;
> + 		intc = &intc;
> +@@ -94,6 +95,11 @@
> + 	clock-frequency = <100000>;
> + };
> +
> ++&i2c2 {
> ++	pinctrl-names = "default";
> ++	clock-frequency = <100000>;
> ++};
> ++
> + &i2s {
> + 	#sound-dai-cells = <0>;
> + 	pinctrl-names = "default";
> +diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c
> +index 8773203b34eb..2054ff44e744 100644
> +--- a/drivers/i2c/busses/i2c-bcm2708.c
> ++++ b/drivers/i2c/busses/i2c-bcm2708.c
> +@@ -109,6 +109,7 @@ static void bcm2708_i2c_init_pinmode(int id)
> + #define SET_GPIO_ALT(g,a) *(gpio+(((g)/10))) |= (((a)<=3?(a)+4:(a)==4?3:2)<<(((g)%10)*3))
> +
> + 	int pin;
> ++
> + 	u32 *gpio = ioremap(GPIO_BASE, SZ_16K);
> +
> + 	BUG_ON(id != 0 && id != 1);
> +@@ -382,7 +383,7 @@ static int bcm2708_i2c_probe(struct platform_device *pdev)
> + 		goto out_clk_put;
> + 	}
> +
> +-	if (!pdev->dev.of_node)
> ++	if (pdev->id < 2)
> + 		bcm2708_i2c_init_pinmode(pdev->id);
> +
> + 	bi = kzalloc(sizeof(*bi), GFP_KERNEL);
> +@@ -407,6 +408,9 @@ static int bcm2708_i2c_probe(struct platform_device *pdev)
> + 	case 1:
> + 		adap->class = I2C_CLASS_DDC;
> + 		break;
> ++	case 2:
> ++		adap->class = I2C_CLASS_DDC;
> ++		break;
> + 	default:
> + 		dev_err(&pdev->dev, "can only bind to BSC 0 or 1\n");
> + 		err = -ENXIO;
> +--
> +2.4.3
> +
> diff --git a/recipes-kernel/linux/linux-raspberrypi/0003-drm-vc4-Use-the-fbdev_cma-helpers.patch b/recipes-kernel/linux/linux-raspberrypi/0003-drm-vc4-Use-the-fbdev_cma-helpers.patch
> new file mode 100644
> index 000000000000..bc50992dcdbe
> --- /dev/null
> +++ b/recipes-kernel/linux/linux-raspberrypi/0003-drm-vc4-Use-the-fbdev_cma-helpers.patch
> @@ -0,0 +1,115 @@
> +From e877e76e5d723eb14bce9c58af40b962eced02bf Mon Sep 17 00:00:00 2001
> +From: Derek Foreman <derekf@osg.samsung.com>
> +Date: Thu, 2 Jul 2015 11:19:54 -0500
> +Subject: [PATCH 3/5] drm/vc4: Use the fbdev_cma helpers
> +
> +Keep the fbdev_cma pointer around so we can use it on hotplog and close
> +to ensure the frame buffer console is in a useful state.
> +
> +Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
> +---
> + drivers/gpu/drm/vc4/vc4_drv.c | 15 +++++++++++++++
> + drivers/gpu/drm/vc4/vc4_drv.h |  2 ++
> + drivers/gpu/drm/vc4/vc4_kms.c | 18 +++++++++++++++---
> + 3 files changed, 32 insertions(+), 3 deletions(-)
> +
> +diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
> +index 5c023ba4f6ad..04f1f738ebc2 100644
> +--- a/drivers/gpu/drm/vc4/vc4_drv.c
> ++++ b/drivers/gpu/drm/vc4/vc4_drv.c
> +@@ -13,6 +13,7 @@
> + #include <linux/module.h>
> + #include <linux/of_platform.h>
> + #include <linux/platform_device.h>
> ++#include <drm/drm_fb_cma_helper.h>
> +
> + #include "uapi/drm/vc4_drm.h"
> + #include "vc4_drv.h"
> +@@ -78,6 +79,11 @@ vc4_drm_load(struct drm_device *dev, unsigned long flags)
> +
> + static int vc4_drm_unload(struct drm_device *dev)
> + {
> ++	struct vc4_dev *vc4 = to_vc4_dev(dev);
> ++
> ++	if (vc4->fbdev)
> ++		drm_fbdev_cma_fini(vc4->fbdev);
> ++
> + 	drm_mode_config_cleanup(dev);
> +
> + 	component_unbind_all(dev->dev, dev);
> +@@ -93,6 +99,14 @@ static void vc4_drm_preclose(struct drm_device *dev, struct drm_file *file)
> + 		vc4_cancel_page_flip(crtc, file);
> + }
> +
> ++static void vc4_lastclose(struct drm_device *dev)
> ++{
> ++	struct vc4_dev *vc4 = to_vc4_dev(dev);
> ++
> ++	if (vc4->fbdev)
> ++		drm_fbdev_cma_restore_mode(vc4->fbdev);
> ++}
> ++
> + static const struct file_operations vc4_drm_fops = {
> + 	.owner = THIS_MODULE,
> + 	.open = drm_open,
> +@@ -123,6 +137,7 @@ static struct drm_driver vc4_drm_driver = {
> + 			    DRIVER_PRIME),
> + 	.load = vc4_drm_load,
> + 	.unload = vc4_drm_unload,
> ++	.lastclose = vc4_lastclose,
> + 	.set_busid = drm_platform_set_busid,
> + 	.preclose = vc4_drm_preclose,
> +
> +diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
> +index 13b475785ca0..d460bb3e6b64 100644
> +--- a/drivers/gpu/drm/vc4/vc4_drv.h
> ++++ b/drivers/gpu/drm/vc4/vc4_drv.h
> +@@ -81,6 +81,8 @@ struct vc4_dev {
> + 	} hangcheck;
> +
> + 	struct semaphore async_modeset;
> ++
> ++	struct drm_fbdev_cma *fbdev;
> + };
> +
> + static inline struct vc4_dev *
> +diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
> +index acfd1b23ab4a..cb18d8f0e387 100644
> +--- a/drivers/gpu/drm/vc4/vc4_kms.c
> ++++ b/drivers/gpu/drm/vc4/vc4_kms.c
> +@@ -155,7 +155,17 @@ static int vc4_atomic_commit(struct drm_device *dev,
> + 	return 0;
> + }
> +
> ++static void vc4_output_poll_changed(struct drm_device *dev)
> ++{
> ++	struct vc4_dev *vc4 = to_vc4_dev(dev);
> ++
> ++	if (vc4->fbdev)
> ++		drm_fbdev_cma_hotplug_event(vc4->fbdev);
> ++}
> ++
> ++
> + static const struct drm_mode_config_funcs vc4_mode_funcs = {
> ++	.output_poll_changed = vc4_output_poll_changed,
> + 	.atomic_check = drm_atomic_helper_check,
> + 	.atomic_commit = vc4_atomic_commit,
> + 	.fb_create = drm_fb_cma_create,
> +@@ -214,9 +224,11 @@ vc4_kms_load(struct drm_device *dev)
> +
> + 	drm_mode_config_reset(dev);
> +
> +-	drm_fbdev_cma_init(dev, 32,
> +-			   dev->mode_config.num_crtc,
> +-			   dev->mode_config.num_connector);
> ++	vc4->fbdev = drm_fbdev_cma_init(dev, 32,
> ++					dev->mode_config.num_crtc,
> ++					dev->mode_config.num_connector);
> ++	if (IS_ERR(vc4->fbdev))
> ++		vc4->fbdev = NULL;
> +
> + 	drm_kms_helper_poll_init(dev);
> +
> +--
> +2.4.3
> +
> diff --git a/recipes-kernel/linux/linux-raspberrypi/0004-drm-vc4-Allow-vblank-to-be-disabled.patch b/recipes-kernel/linux/linux-raspberrypi/0004-drm-vc4-Allow-vblank-to-be-disabled.patch
> new file mode 100644
> index 000000000000..0293ed713c3e
> --- /dev/null
> +++ b/recipes-kernel/linux/linux-raspberrypi/0004-drm-vc4-Allow-vblank-to-be-disabled.patch
> @@ -0,0 +1,26 @@
> +From 4388ed0f2d66399a6ad3133b91bd438cdb25e37b Mon Sep 17 00:00:00 2001
> +From: Derek Foreman <derekf@osg.samsung.com>
> +Date: Thu, 2 Jul 2015 11:20:21 -0500
> +Subject: [PATCH 4/5] drm/vc4: Allow vblank to be disabled
> +
> +Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
> +---
> + drivers/gpu/drm/vc4/vc4_kms.c | 2 ++
> + 1 file changed, 2 insertions(+)
> +
> +diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
> +index cb18d8f0e387..1473df9ef4a1 100644
> +--- a/drivers/gpu/drm/vc4/vc4_kms.c
> ++++ b/drivers/gpu/drm/vc4/vc4_kms.c
> +@@ -218,6 +218,8 @@ vc4_kms_load(struct drm_device *dev)
> + 	dev->mode_config.funcs = &vc4_mode_funcs;
> + 	dev->mode_config.preferred_depth = 24;
> +
> ++	dev->vblank_disable_allowed = true;
> ++
> + 	ret = vc4_init_modeset_objects(dev);
> + 	if (ret)
> + 		goto fail;
> +--
> +2.4.3
> +
> diff --git a/recipes-kernel/linux/linux-raspberrypi/0005-drm-vc4-Disable-KMS-operations.patch b/recipes-kernel/linux/linux-raspberrypi/0005-drm-vc4-Disable-KMS-operations.patch
> new file mode 100644
> index 000000000000..eff5058aeda7
> --- /dev/null
> +++ b/recipes-kernel/linux/linux-raspberrypi/0005-drm-vc4-Disable-KMS-operations.patch
> @@ -0,0 +1,95 @@
> +From 844a32b8444a38b6378c98ad4a4b8b8c3522c020 Mon Sep 17 00:00:00 2001
> +From: Derek Foreman <derekf@osg.samsung.com>
> +Date: Fri, 24 Jul 2015 03:29:15 +0200
> +Subject: [PATCH 5/5] drm/vc4: Disable KMS operations
> +
> +The vc4 driver KMS implementation still has some issues so
> +for now skip most of the codepaths to avoid system hangs.
> +
> +Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
> +---
> + drivers/gpu/drm/drm_atomic_helper.c | 2 +-
> + drivers/gpu/drm/vc4/vc4_crtc.c      | 2 +-
> + drivers/gpu/drm/vc4/vc4_hdmi.c      | 6 ++++--
> + drivers/gpu/drm/vc4/vc4_kms.c       | 1 +
> + 4 files changed, 7 insertions(+), 4 deletions(-)
> +
> +diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> +index 1d2ca52530d5..ba7f355bcced 100644
> +--- a/drivers/gpu/drm/drm_atomic_helper.c
> ++++ b/drivers/gpu/drm/drm_atomic_helper.c
> +@@ -1876,7 +1876,7 @@ void drm_atomic_helper_connector_dpms(struct drm_connector *connector,
> + 	struct drm_connector *tmp_connector;
> + 	int ret;
> + 	bool active = false;
> +-
> ++return;
> + 	if (mode != DRM_MODE_DPMS_ON)
> + 		mode = DRM_MODE_DPMS_OFF;
> +
> +diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
> +index f9960ac34fd7..1b85355baef0 100644
> +--- a/drivers/gpu/drm/vc4/vc4_crtc.c
> ++++ b/drivers/gpu/drm/vc4/vc4_crtc.c
> +@@ -91,7 +91,7 @@ static void vc4_crtc_mode_set_nofb(struct drm_crtc *crtc)
> + 		       ((mode->flags & DRM_MODE_FLAG_INTERLACE) ? 1 : 0));
> + 	u32 format = PV_CONTROL_FORMAT_24;
> + 	bool debug_dump_regs = false;
> +-
> ++return;
> + 	if (debug_dump_regs) {
> + 		DRM_INFO("CRTC %d regs before:\n", drm_crtc_index(crtc));
> + 		vc4_crtc_dump_regs(vc4_crtc);
> +diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> +index 8c41fdc4ef2e..2a212b08e108 100644
> +--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> ++++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> +@@ -273,7 +273,7 @@ vc4_set_pixel_clock(struct vc4_dev *vc4, u32 clock)
> + {
> + 	u32 packet[2];
> + 	int ret;
> +-
> ++return;
> + 	packet[0] = 8; /* Pixel clock. */
> + 	packet[1] = clock;
> +
> +@@ -295,6 +295,7 @@ static void vc4_hdmi_encoder_mode_set(struct drm_encoder *encoder,
> + 	bool debug_dump_regs = false;
> + 	bool hsync_pos = !(mode->flags & DRM_MODE_FLAG_NHSYNC);
> + 	bool vsync_pos = !(mode->flags & DRM_MODE_FLAG_NVSYNC);
> ++return;
> + 	u32 vactive = (mode->vdisplay >>
> + 		       ((mode->flags & DRM_MODE_FLAG_INTERLACE) ? 1 : 0));
> + 	u32 verta = (VC4_SET_FIELD(mode->vsync_end - mode->vsync_start,
> +@@ -405,7 +406,7 @@ static void vc4_hdmi_encoder_disable(struct drm_encoder *encoder)
> + {
> + 	struct drm_device *dev = encoder->dev;
> + 	struct vc4_dev *vc4 = to_vc4_dev(dev);
> +-
> ++return;
> + 	HDMI_WRITE(VC4_HDMI_TX_PHY_RESET_CTL, 0xf << 16);
> + }
> +
> +@@ -413,6 +414,7 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder)
> + {
> + 	struct drm_device *dev = encoder->dev;
> + 	struct vc4_dev *vc4 = to_vc4_dev(dev);
> ++return;
> +
> + 	HDMI_WRITE(VC4_HDMI_TX_PHY_RESET_CTL, 0);
> + }
> +diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
> +index 1473df9ef4a1..5ddc5d9beaae 100644
> +--- a/drivers/gpu/drm/vc4/vc4_kms.c
> ++++ b/drivers/gpu/drm/vc4/vc4_kms.c
> +@@ -144,6 +144,7 @@ static int vc4_atomic_commit(struct drm_device *dev,
> + 	 * current layout.
> + 	 */
> +
> ++	async=0;
> + 	if (async) {
> + 		vc4_queue_seqno_cb(dev, &c->cb, wait_seqno,
> + 				   vc4_atomic_complete_commit_seqno_cb);
> +--
> +2.4.3
> +
> diff --git a/recipes-kernel/linux/linux-raspberrypi_4.1.bb b/recipes-kernel/linux/linux-raspberrypi_4.1.bb

We will have to rename this because the linux-raspberrypi recipes are known
from the raspberrypi linux fork. So maybe havinf something like:
linux-raspberrypi-vc4?

> new file mode 100644
> index 000000000000..a8e1863ddf2c
> --- /dev/null
> +++ b/recipes-kernel/linux/linux-raspberrypi_4.1.bb
> @@ -0,0 +1,16 @@
> +LINUX_VERSION ?= "4.1.0"
> +
> +# Don't make this the default kernel, right now it is only for testing purposes
> +DEFAULT_PREFERENCE = "-1"
> +
> +SRCREV = "07009cab090ade3dd180e8a55d590b1a00072eed"
> +SRC_URI = "git://github.com/anholt/linux.git;protocol=git;branch=vc4-kms-v3d-rpi2"
> +
> +# Add patches needed for the vc4 driver but only if enabled as distro feature since are experimental
> +SRC_URI += "${@bb.utils.contains('DISTRO_FEATURES', 'vc4-gfx', 'file://0001-ARM-bcm2709_defconfig-Enable-config-options-for-vc4-.patch', '', d)}"
> +SRC_URI += "${@bb.utils.contains('DISTRO_FEATURES', 'vc4-gfx', 'file://0002-ARM-dts-Fix-i2c-for-bcm2709-RPI2-B-board.patch', '', d)}"
> +SRC_URI += "${@bb.utils.contains('DISTRO_FEATURES', 'vc4-gfx', 'file://0003-drm-vc4-Use-the-fbdev_cma-helpers.patch', '', d)}"
> +SRC_URI += "${@bb.utils.contains('DISTRO_FEATURES', 'vc4-gfx', 'file://0004-drm-vc4-Allow-vblank-to-be-disabled.patch', '', d)}"
> +SRC_URI += "${@bb.utils.contains('DISTRO_FEATURES', 'vc4-gfx', 'file://0005-drm-vc4-Disable-KMS-operations.patch', '', d)}"
> +

I don't see the need of the selective inclusion as this fork is a vc4 one. So,
as long as you select this provider, you will need the patches.

> +require linux-raspberrypi.inc
> --
> 2.4.3
>

--
Andrei Gherzan