From 52304886ea49ee662589aff05925ef226c17a6a6 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Thu, 26 Oct 2023 15:53:03 +0200 Subject: [PATCH] ACPI: video: Add comment about acpi_video_backlight_use_native() usage Add a comment explaining that acpi_video_backlight_use_native() MUST only be used by GPU drivers and that it must NOT be used on other places. Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki --- include/acpi/video.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/include/acpi/video.h b/include/acpi/video.h index 4230392b5b0b..3d538d4178ab 100644 --- a/include/acpi/video.h +++ b/include/acpi/video.h @@ -75,6 +75,15 @@ static inline enum acpi_backlight_type acpi_video_get_backlight_type(void) return __acpi_video_get_backlight_type(false, NULL); } +/* + * This function MUST only be called by GPU drivers to check if the driver + * should register a backlight class device. This function not only checks + * if a GPU native backlight device should be registered it *also* tells + * the ACPI video-detect code that native GPU backlight control is available. + * Therefor calling this from any place other then the GPU driver is wrong! + * To check if GPU native backlight control is used in other places instead use: + * if (acpi_video_get_backlight_type() == acpi_backlight_native) { ... } + */ static inline bool acpi_video_backlight_use_native(void) { return __acpi_video_get_backlight_type(true, NULL) == acpi_backlight_native;