From 2600bfa3df9944562d43d1f17016832a6ffa3b38 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Fri, 15 Apr 2022 13:59:48 +0200 Subject: ACPI: video: Add acpi_video_backlight_use_native() helper ATM on x86 laptops where we want userspace to use the acpi_video backlight device we often register both the GPU's native backlight device and acpi_video's firmware acpi_video# backlight device. This relies on userspace preferring firmware type backlight devices over native ones, but registering 2 backlight devices for a single display really is undesirable. On x86 laptops where the native GPU backlight device should be used, the registering of other backlight devices is avoided by their drivers using acpi_video_get_backlight_type() and only registering their backlight if the return value matches their type. acpi_video_get_backlight_type() uses backlight_device_get_by_type(BACKLIGHT_RAW) to determine if a native driver is available and will never return native if this returns false. This means that the GPU's native backlight registering code cannot just call acpi_video_get_backlight_type() to determine if it should register its backlight, since acpi_video_get_backlight_type() will never return native until the native backlight has already registered. To fix this add a new internal native function parameter to acpi_video_get_backlight_type(), which when set to true will make acpi_video_get_backlight_type() behave as if a native backlight has already been registered. And add a new acpi_video_backlight_use_native() helper, which sets this to true, for use in native GPU backlight code. Changes in v2: - Replace adding a native parameter to acpi_video_get_backlight_type() with adding a new acpi_video_backlight_use_native() helper. Acked-by: Rafael J. Wysocki Signed-off-by: Hans de Goede --- include/acpi/video.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include') diff --git a/include/acpi/video.h b/include/acpi/video.h index db8548ff03ce..4705e339c252 100644 --- a/include/acpi/video.h +++ b/include/acpi/video.h @@ -56,6 +56,7 @@ extern void acpi_video_unregister(void); extern int acpi_video_get_edid(struct acpi_device *device, int type, int device_id, void **edid); extern enum acpi_backlight_type acpi_video_get_backlight_type(void); +extern bool acpi_video_backlight_use_native(void); extern void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type); /* * Note: The value returned by acpi_video_handles_brightness_key_presses() @@ -77,6 +78,10 @@ static inline enum acpi_backlight_type acpi_video_get_backlight_type(void) { return acpi_backlight_vendor; } +static inline bool acpi_video_backlight_use_native(void) +{ + return true; +} static inline void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type) { } -- cgit v1.2.3