From 3c8b6a399e0eaa6ab839bba2ce9a2bc57e6708d6 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sat, 30 Apr 2022 15:54:36 +0200 Subject: drm/i915: Call acpi_video_register_backlight() (v3) On machins without an i915 opregion the acpi_video driver immediately probes the ACPI video bus and used to also immediately register acpi_video# backlight devices when supported. Once the drm/kms driver then loaded later and possibly registered a native backlight device then the drivers/acpi/video_detect.c code unregistered the acpi_video0 device to avoid there being 2 backlight devices (when acpi_video_get_backlight_type()==native). 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() after the i915 calls acpi_video_register() (after setting up the i915 opregion) so that the acpi_video backlight devices get registered on systems where the i915 native backlight device is not registered. Changes in v2: -Only call acpi_video_register_backlight() when a panel is detected Changes in v3: -Add a new intel_acpi_video_register() helper which checks if a panel is present and then calls acpi_video_register_backlight() Reviewed-by: Jani Nikula Signed-off-by: Hans de Goede --- drivers/gpu/drm/i915/display/intel_acpi.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/gpu/drm/i915/display/intel_acpi.h') diff --git a/drivers/gpu/drm/i915/display/intel_acpi.h b/drivers/gpu/drm/i915/display/intel_acpi.h index 4a760a2baed9..6a0007452f95 100644 --- a/drivers/gpu/drm/i915/display/intel_acpi.h +++ b/drivers/gpu/drm/i915/display/intel_acpi.h @@ -14,6 +14,7 @@ void intel_unregister_dsm_handler(void); void intel_dsm_get_bios_data_funcs_supported(struct drm_i915_private *i915); void intel_acpi_device_id_update(struct drm_i915_private *i915); void intel_acpi_assign_connector_fwnodes(struct drm_i915_private *i915); +void intel_acpi_video_register(struct drm_i915_private *i915); #else static inline void intel_register_dsm_handler(void) { return; } static inline void intel_unregister_dsm_handler(void) { return; } @@ -23,6 +24,8 @@ static inline void intel_acpi_device_id_update(struct drm_i915_private *i915) { return; } static inline void intel_acpi_assign_connector_fwnodes(struct drm_i915_private *i915) { return; } +static inline +void intel_acpi_video_register(struct drm_i915_private *i915) { return; } #endif /* CONFIG_ACPI */ #endif /* __INTEL_ACPI_H__ */ -- cgit v1.2.3