Just one tiny nitpick below: On Wed, 2022-08-24 at 14:14 +0200, Hans de Goede wrote: > Before this commit when we want userspace to use the acpi_video backlight > device we 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. > > Registering 2 backlight devices for a single display really is > undesirable, don't register the GPU's native backlight device when > another backlight device should be used. > > Changes in v2: > - Add nouveau_acpi_video_backlight_use_native() wrapper to avoid unresolved > symbol errors on non X86 > > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> > --- > drivers/gpu/drm/nouveau/nouveau_acpi.c | 5 +++++ > drivers/gpu/drm/nouveau/nouveau_acpi.h | 2 ++ > drivers/gpu/drm/nouveau/nouveau_backlight.c | 6 ++++++ > 3 files changed, 13 insertions(+) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c > index 6140db756d06..1592c9cd7750 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_acpi.c > +++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c > @@ -386,3 +386,8 @@ nouveau_acpi_edid(struct drm_device *dev, struct drm_connector *connector) > > return kmemdup(edid, EDID_LENGTH, GFP_KERNEL); > } > + > +bool nouveau_acpi_video_backlight_use_native(void) > +{ > + return acpi_video_backlight_use_native(); > +} > diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.h b/drivers/gpu/drm/nouveau/nouveau_acpi.h > index 330f9b837066..3c666c30dfca 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_acpi.h > +++ b/drivers/gpu/drm/nouveau/nouveau_acpi.h > @@ -11,6 +11,7 @@ void nouveau_register_dsm_handler(void); > void nouveau_unregister_dsm_handler(void); > void nouveau_switcheroo_optimus_dsm(void); > void *nouveau_acpi_edid(struct drm_device *, struct drm_connector *); > +bool nouveau_acpi_video_backlight_use_native(void); > #else > static inline bool nouveau_is_optimus(void) { return false; }; > static inline bool nouveau_is_v1_dsm(void) { return false; }; > @@ -18,6 +19,7 @@ static inline void nouveau_register_dsm_handler(void) {} > static inline void nouveau_unregister_dsm_handler(void) {} > static inline void nouveau_switcheroo_optimus_dsm(void) {} > static inline void *nouveau_acpi_edid(struct drm_device *dev, struct drm_connector *connector) { return NULL; } > +static inline bool nouveau_acpi_video_backlight_use_native(void) { return true; } > #endif > > #endif > diff --git a/drivers/gpu/drm/nouveau/nouveau_backlight.c b/drivers/gpu/drm/nouveau/nouveau_backlight.c > index a2141d3d9b1d..d2b8f8c13db4 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_backlight.c > +++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c > @@ -38,6 +38,7 @@ > #include "nouveau_reg.h" > #include "nouveau_encoder.h" > #include "nouveau_connector.h" > +#include "nouveau_acpi.h" > > static struct ida bl_ida; > #define BL_NAME_SIZE 15 // 12 for name + 2 for digits + 1 for '\0' > @@ -405,6 +406,11 @@ nouveau_backlight_init(struct drm_connector *connector) > goto fail_alloc; > } > > + if (!nouveau_acpi_video_backlight_use_native()) { > + NV_INFO(drm, "Skipping nv_backlight registration\n"); > + goto fail_alloc; > + } We should probably make this say something like "No native backlight interface, using ACPI instead" instead. With that fixed Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx> > + > if (!nouveau_get_backlight_name(backlight_name, bl)) { > NV_ERROR(drm, "Failed to retrieve a unique name for the backlight interface\n"); > goto fail_alloc; -- Cheers, Lyude Paul (she/her) Software Engineer at Red Hat