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 ? 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; >
