[RESEND][PATCH v1 0/3] ACPI: video: Convert ACPI video driver to a platform one

[RESEND][PATCH v1 0/3] ACPI: video: Convert ACPI video driver to a platform one

[Rafael J. Wysocki]

Hi All,

This is a resend of

https://lore.kernel.org/linux-acpi/8617910.T7Z3S40VBb@rafael.j.wysocki/

due to the lack of feedback.

It applies on top of the ACPI patches in linux-next.

The original cover letter still applies.

Thanks!

[RESEND][PATCH v1 1/3] ACPI: scan: Register platform devices for backlight device objects

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

ACPI device objects associated with backlight interfaces are special
because they are ACPI companions of PCI devices (GPUs), but the
interfaces exposed by them resemble platform device one.

Currently, the ACPI video driver binds to them with the help of a
special "synthetic" device ID regardless of the pairing with the PCI
devices, but since it is generally better to use platform drivers for
handling such interfaces, the plan is to convert that drviver into a
platform one.

However, for this purpose, platform devices corresponding to the
ACPI backlight device objects need to be registered, so update
acpi_bus_attach() to apply the default ACPI enumeration to them
and modify acpi_create_platform_device() to avoid bailing out early
if a "physical" device is already attached to a backlight ACPI device
object.

In addition, update acpi_companion_match() to return a valid struct
acpi_device pointer if the ACPI companion of the given device is a
backlight ACPI device object, which will facilitate driver matching
for platform devices corresponding to those objects.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/acpi_platform.c | 4 ++--
 drivers/acpi/bus.c           | 3 +++
 drivers/acpi/scan.c          | 3 ++-
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
index 52c8d602f3a5..377ca8324121 100644
--- a/drivers/acpi/acpi_platform.c
+++ b/drivers/acpi/acpi_platform.c
@@ -118,7 +118,7 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
 	int count = 0;
 
 	/* If the ACPI node already has a physical device attached, skip it. */
-	if (adev->physical_node_count)
+	if (adev->physical_node_count && !adev->pnp.type.backlight)
 		return NULL;
 
 	match = acpi_match_acpi_device(forbidden_id_list, adev);
@@ -135,7 +135,7 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
 		}
 	}
 
-	if (adev->device_type == ACPI_BUS_TYPE_DEVICE) {
+	if (adev->device_type == ACPI_BUS_TYPE_DEVICE && !adev->pnp.type.backlight) {
 		struct list_head resource_list = LIST_HEAD_INIT(resource_list);
 
 		count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index a984ccd4a2a0..574e190f6bf9 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -761,6 +761,9 @@ const struct acpi_device *acpi_companion_match(const struct device *dev)
 	if (list_empty(&adev->pnp.ids))
 		return NULL;
 
+	if (adev->pnp.type.backlight)
+		return adev;
+
 	return acpi_primary_dev_companion(adev, dev);
 }
 
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index d0479ac40856..360d82378e56 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2350,7 +2350,8 @@ static int acpi_bus_attach(struct acpi_device *device, void *first_pass)
 	if (ret < 0)
 		return 0;
 
-	if (device->pnp.type.platform_id || device->flags.enumeration_by_parent)
+	if (device->pnp.type.platform_id || device->pnp.type.backlight ||
+	    device->flags.enumeration_by_parent)
 		acpi_default_enumeration(device);
 	else
 		acpi_device_set_enumerated(device);
-- 
2.51.0

[RESEND][PATCH v1 2/3] ACPI: video: Adjust event notification routine

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

Adjust acpi_video_bus_notify() to cast its "data" argument to a struct
acpi_video_bus pointer instead of a struct acpi_device one, which allows
the use of acpi_driver_data() to be limited and will facilitate
subsequent changes.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/acpi_video.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index be8e7e18abca..54e09e7f8e77 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -1540,14 +1540,11 @@ static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
 
 static void acpi_video_bus_notify(acpi_handle handle, u32 event, void *data)
 {
-	struct acpi_device *device = data;
-	struct acpi_video_bus *video = acpi_driver_data(device);
+	struct acpi_video_bus *video = data;
+	struct acpi_device *device = video->device;
 	struct input_dev *input;
 	int keycode = 0;
 
-	if (!video || !video->input)
-		return;
-
 	input = video->input;
 
 	switch (event) {
@@ -2076,7 +2073,7 @@ static int acpi_video_bus_add(struct acpi_device *device)
 		goto err_del;
 
 	error = acpi_dev_install_notify_handler(device, ACPI_DEVICE_NOTIFY,
-						acpi_video_bus_notify, device);
+						acpi_video_bus_notify, video);
 	if (error)
 		goto err_remove;
 
-- 
2.51.0

[RESEND][PATCH v1 3/3] ACPI: video: Convert the driver to a platform one

[Rafael J. Wysocki]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

While binding drivers directly to struct acpi_device objects allows
basic functionality to be provided, at least in the majority of cases,
there are some problems with it, related to general consistency, sysfs
layout, power management operation ordering, and code cleanliness.

Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the ACPI video driver to a platform one.

While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/acpi_video.c | 47 +++++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 24 deletions(-)

diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index 54e09e7f8e77..944aba605c1a 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -21,6 +21,7 @@
 #include <linux/sort.h>
 #include <linux/pci.h>
 #include <linux/pci_ids.h>
+#include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/dmi.h>
 #include <linux/suspend.h>
@@ -76,8 +77,8 @@ static int register_count;
 static DEFINE_MUTEX(register_count_mutex);
 static DEFINE_MUTEX(video_list_lock);
 static LIST_HEAD(video_bus_head);
-static int acpi_video_bus_add(struct acpi_device *device);
-static void acpi_video_bus_remove(struct acpi_device *device);
+static int acpi_video_bus_probe(struct platform_device *pdev);
+static void acpi_video_bus_remove(struct platform_device *pdev);
 static void acpi_video_bus_notify(acpi_handle handle, u32 event, void *data);
 
 /*
@@ -98,14 +99,13 @@ static const struct acpi_device_id video_device_ids[] = {
 };
 MODULE_DEVICE_TABLE(acpi, video_device_ids);
 
-static struct acpi_driver acpi_video_bus = {
-	.name = "video",
-	.class = ACPI_VIDEO_CLASS,
-	.ids = video_device_ids,
-	.ops = {
-		.add = acpi_video_bus_add,
-		.remove = acpi_video_bus_remove,
-		},
+static struct platform_driver acpi_video_bus = {
+	.probe = acpi_video_bus_probe,
+	.remove = acpi_video_bus_remove,
+	.driver = {
+		.name = "acpi-video",
+		.acpi_match_table = video_device_ids,
+	},
 };
 
 struct acpi_video_bus_flags {
@@ -1888,7 +1888,8 @@ static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
 		device->flags.notify = 1;
 }
 
-static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
+static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video,
+					     struct platform_device *pdev)
 {
 	struct input_dev *input;
 	struct acpi_video_device *dev;
@@ -1911,7 +1912,7 @@ static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
 	input->phys = video->phys;
 	input->id.bustype = BUS_HOST;
 	input->id.product = 0x06;
-	input->dev.parent = &video->device->dev;
+	input->dev.parent = &pdev->dev;
 	input->evbit[0] = BIT(EV_KEY);
 	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
 	set_bit(KEY_VIDEO_NEXT, input->keybit);
@@ -1983,8 +1984,9 @@ static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
 
 static int instance;
 
-static int acpi_video_bus_add(struct acpi_device *device)
+static int acpi_video_bus_probe(struct platform_device *pdev)
 {
+	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
 	struct acpi_video_bus *video;
 	bool auto_detect;
 	int error;
@@ -2021,6 +2023,8 @@ static int acpi_video_bus_add(struct acpi_device *device)
 		instance++;
 	}
 
+	platform_set_drvdata(pdev, video);
+
 	video->device = device;
 	strscpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
 	strscpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
@@ -2068,7 +2072,7 @@ static int acpi_video_bus_add(struct acpi_device *device)
 	    !auto_detect)
 		acpi_video_bus_register_backlight(video);
 
-	error = acpi_video_bus_add_notify_handler(video);
+	error = acpi_video_bus_add_notify_handler(video, pdev);
 	if (error)
 		goto err_del;
 
@@ -2096,15 +2100,10 @@ static int acpi_video_bus_add(struct acpi_device *device)
 	return error;
 }
 
-static void acpi_video_bus_remove(struct acpi_device *device)
+static void acpi_video_bus_remove(struct platform_device *pdev)
 {
-	struct acpi_video_bus *video = NULL;
-
-
-	if (!device || !acpi_driver_data(device))
-		return;
-
-	video = acpi_driver_data(device);
+	struct acpi_video_bus *video = platform_get_drvdata(pdev);
+	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
 
 	acpi_dev_remove_notify_handler(device, ACPI_DEVICE_NOTIFY,
 				       acpi_video_bus_notify);
@@ -2167,7 +2166,7 @@ int acpi_video_register(void)
 
 	dmi_check_system(video_dmi_table);
 
-	ret = acpi_bus_register_driver(&acpi_video_bus);
+	ret = platform_driver_register(&acpi_video_bus);
 	if (ret)
 		goto leave;
 
@@ -2187,7 +2186,7 @@ void acpi_video_unregister(void)
 {
 	mutex_lock(&register_count_mutex);
 	if (register_count) {
-		acpi_bus_unregister_driver(&acpi_video_bus);
+		platform_driver_unregister(&acpi_video_bus);
 		register_count = 0;
 		may_report_brightness_keys = false;
 	}
-- 
2.51.0

Re: [RESEND][PATCH v1 0/3] ACPI: video: Convert ACPI video driver to a platform one

[Hans de Goede]

Hi Rafael,

On 2-Jan-26 12:48, Rafael J. Wysocki wrote:
> Hi All,
> 
> This is a resend of
> 
> https://lore.kernel.org/linux-acpi/8617910.T7Z3S40VBb@rafael.j.wysocki/
> 
> due to the lack of feedback.

Sorry for not being able to provide feedback. I'm still getting
up 2 speed wrt my new position at Qualcomm so atm I don't really
have time to look into this.

I do plan to add linux-pm/linux-next + these patches to my local
kernel so that they get some testing that way. If I hit any issues
I'll let you know.

Regards,

Hans

Re: [RESEND][PATCH v1 0/3] ACPI: video: Convert ACPI video driver to a platform one

[Rafael J. Wysocki]

Hi Hans,

On Mon, Jan 5, 2026 at 4:42 PM Hans de Goede <hansg@kernel.org> wrote:
>
> Hi Rafael,
>
> On 2-Jan-26 12:48, Rafael J. Wysocki wrote:
> > Hi All,
> >
> > This is a resend of
> >
> > https://lore.kernel.org/linux-acpi/8617910.T7Z3S40VBb@rafael.j.wysocki/
> >
> > due to the lack of feedback.
>
> Sorry for not being able to provide feedback. I'm still getting
> up 2 speed wrt my new position at Qualcomm so atm I don't really
> have time to look into this.

No worries.

> I do plan to add linux-pm/linux-next + these patches to my local
> kernel so that they get some testing that way. If I hit any issues
> I'll let you know.

Thank you!

Re: [RESEND][PATCH v1 0/3] ACPI: video: Convert ACPI video driver to a platform one

[Armin Wolf]

Am 02.01.26 um 12:48 schrieb Rafael J. Wysocki:

> Hi All,
>
> This is a resend of
>
> https://lore.kernel.org/linux-acpi/8617910.T7Z3S40VBb@rafael.j.wysocki/
>
> due to the lack of feedback.
>
> It applies on top of the ACPI patches in linux-next.

I am somehow unable to apply this series onto linux-next. Can you send a new series that
can be applied on the current linux-next?

Thanks,
Armin Wolf

>
> The original cover letter still applies.
>
> Thanks!
>
>
>
>
>

Re: [RESEND][PATCH v1 0/3] ACPI: video: Convert ACPI video driver to a platform one

[Rafael J. Wysocki]

On Mon, Jan 12, 2026 at 9:19 PM Armin Wolf <W_Armin@gmx.de> wrote:
>
> Am 02.01.26 um 12:48 schrieb Rafael J. Wysocki:
>
> > Hi All,
> >
> > This is a resend of
> >
> > https://lore.kernel.org/linux-acpi/8617910.T7Z3S40VBb@rafael.j.wysocki/
> >
> > due to the lack of feedback.
> >
> > It applies on top of the ACPI patches in linux-next.
>
> I am somehow unable to apply this series onto linux-next. Can you send a new series that
> can be applied on the current linux-next?

It should be there in linux-next already, sorry for forgetting to mention that.

Re: [RESEND][PATCH v1 0/3] ACPI: video: Convert ACPI video driver to a platform one

[Armin Wolf]

Am 02.01.26 um 12:48 schrieb Rafael J. Wysocki:

> Hi All,
>
> This is a resend of
>
> https://lore.kernel.org/linux-acpi/8617910.T7Z3S40VBb@rafael.j.wysocki/
>
> due to the lack of feedback.
>
> It applies on top of the ACPI patches in linux-next.
>
> The original cover letter still applies.
>
> Thanks!

I finally found some time to test this series on a machine that has a working
ACPI backlight implementation. I only booted inside a minimal console environment,
but i was able to still control the backlight using the acpi-video driver.

I also verified that acpi-video was bound to the correct platform device, and that
the backlight device was still associated with the correct PCI device belonging to
the integrated GPU.

So for the whole series:
Reviewed-by: Armin Wolf <W_Armin@gmx.de>

Thanks,
Armin Wolf

Re: [RESEND][PATCH v1 0/3] ACPI: video: Convert ACPI video driver to a platform one

[Rafael J. Wysocki]

On Wed, Jan 14, 2026 at 11:57 PM Armin Wolf <W_Armin@gmx.de> wrote:
>
> Am 02.01.26 um 12:48 schrieb Rafael J. Wysocki:
>
> > Hi All,
> >
> > This is a resend of
> >
> > https://lore.kernel.org/linux-acpi/8617910.T7Z3S40VBb@rafael.j.wysocki/
> >
> > due to the lack of feedback.
> >
> > It applies on top of the ACPI patches in linux-next.
> >
> > The original cover letter still applies.
> >
> > Thanks!
>
> I finally found some time to test this series on a machine that has a working
> ACPI backlight implementation. I only booted inside a minimal console environment,
> but i was able to still control the backlight using the acpi-video driver.
>
> I also verified that acpi-video was bound to the correct platform device, and that
> the backlight device was still associated with the correct PCI device belonging to
> the integrated GPU.
>
> So for the whole series:
> Reviewed-by: Armin Wolf <W_Armin@gmx.de>

Thank you!