On Wed, 24 Aug 2022, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > > On 8/24/22 14:47, Jani Nikula wrote: >> On Wed, 24 Aug 2022, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: >>> 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 >>> >>> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> >>> --- >>> drivers/gpu/drm/i915/display/intel_display.c | 8 ++++++++ >>> drivers/gpu/drm/i915/display/intel_panel.c | 3 +++ >>> drivers/gpu/drm/i915/i915_drv.h | 2 ++ >>> 3 files changed, 13 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c >>> index 6103b02c081f..2bb53efdb149 100644 >>> --- a/drivers/gpu/drm/i915/display/intel_display.c >>> +++ b/drivers/gpu/drm/i915/display/intel_display.c >>> @@ -9088,6 +9088,14 @@ void intel_display_driver_register(struct drm_i915_private *i915) >>> /* Must be done after probing outputs */ >>> intel_opregion_register(i915); >>> acpi_video_register(); >>> + /* >>> + * Only call this if i915 is driving the internal panel. If the internal >>> + * panel is not driven by i915 then another GPU driver may still register >>> + * a native backlight driver later and this should only be called after >>> + * any native backlights have been registered. >>> + */ >>> + if (i915->have_panel) >>> + acpi_video_register_backlight(); >> >> Apologies for procrastinating the review. >> >> Please let's not add new flags like have_panel to i915; we're trying to >> clean it up instead. >> >> The code here needs to iterate over the connectors to decide. Maybe >> better abstracted a function. > > So something like add a i915_have_panel() helper which iterates over all > the connectors and then of 1 of them is of the LVDS / eDP / DSI type > return true ? Or abstract the acpi_video_register_backlight() calling in a function that does the loop and calls if necessary. BR, Jani. > > Regards, > > Hans > > > >>> intel_audio_init(i915); >>> >>> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c >>> index 237a40623dd7..4536c527f50c 100644 >>> --- a/drivers/gpu/drm/i915/display/intel_panel.c >>> +++ b/drivers/gpu/drm/i915/display/intel_panel.c >>> @@ -646,8 +646,11 @@ intel_panel_mode_valid(struct intel_connector *connector, >>> >>> int intel_panel_init(struct intel_connector *connector) >>> { >>> + struct drm_i915_private *dev_priv = to_i915(connector->base.dev); >>> struct intel_panel *panel = &connector->panel; >>> >>> + dev_priv->have_panel = true; >>> + >>> intel_backlight_init_funcs(panel); >>> >>> drm_dbg_kms(connector->base.dev, >>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h >>> index 69ce6db6a7c1..14b0dcaf25c2 100644 >>> --- a/drivers/gpu/drm/i915/i915_drv.h >>> +++ b/drivers/gpu/drm/i915/i915_drv.h >>> @@ -756,6 +756,8 @@ struct drm_i915_private { >>> >>> bool ipc_enabled; >>> >>> + bool have_panel; >>> + >>> struct intel_audio_private audio; >>> >>> struct i915_pmu pmu; >> > -- Jani Nikula, Intel Open Source Graphics Center
