Commit c0533838 authored by Hans de Goede's avatar Hans de Goede
Browse files

drm/nouveau: Register ACPI video backlight when nv_backlight registration fails (v2) 

Typically the acpi_video driver will initialize before nouveau, which
used to cause /sys/class/backlight/acpi_video0 to get registered and then
nouveau would register its own nv_backlight device later. After which
the drivers/acpi/video_detect.c code unregistered the acpi_video0 device
to avoid there being 2 backlight devices.

This means that userspace used to briefly see 2 devices and the
disappearing of acpi_video0 after a brief time confuses the systemd
backlight level save/restore code, see e.g.:
https://bbs.archlinux.org/viewtopic.php?id=269920



To fix this the ACPI video code has been modified to make backlight class
device registration a separate step, relying on the drm/kms driver to
ask for the acpi_video backlight registration after it is done setting up
its native backlight device.

Add a call to the new acpi_video_register_backlight() when native backlight
device registration has failed / was skipped to ensure that there is a
backlight device available before the drm_device gets registered with
userspace.

Changes in v2:
- Add nouveau_acpi_video_register_backlight() wrapper to avoid unresolved
  symbol errors on non X86

Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
parent 3c8b6a39

drivers/gpu/drm/nouveau/nouveau_acpi.c

+5 −0
Original line number Diff line number Diff line
@@ -391,3 +391,8 @@ bool nouveau_acpi_video_backlight_use_native(void) 
{

	return acpi_video_backlight_use_native();

}



void nouveau_acpi_video_register_backlight(void)

{

	acpi_video_register_backlight();

}

drivers/gpu/drm/nouveau/nouveau_acpi.h

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 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);

void nouveau_acpi_video_register_backlight(void);

#else

static inline bool nouveau_is_optimus(void) { return false; };

static inline bool nouveau_is_v1_dsm(void) { return false; };
@@ -20,6 +21,7 @@ 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; }

static inline void nouveau_acpi_video_register_backlight(void) {}

#endif



#endif

drivers/gpu/drm/nouveau/nouveau_backlight.c

+7 −0
Original line number Diff line number Diff line
@@ -436,6 +436,13 @@ nouveau_backlight_init(struct drm_connector *connector) 


fail_alloc:

	kfree(bl);

	/*

	 * If we get here we have an internal panel, but no nv_backlight,

	 * try registering an ACPI video backlight device instead.

	 */

	if (ret == 0)

		nouveau_acpi_video_register_backlight();



	return ret;

}