| Message ID | 20220824121523.1291269-12-hdegoede@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/kms: Stop registering multiple /sys/class/backlight devs for a single display | expand |
On Wed, 24 Aug 2022, Hans de Goede <hdegoede@redhat.com> 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@redhat.com> > --- > 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. BR, Jani. > > 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;
Hi, On 8/24/22 14:47, Jani Nikula wrote: > On Wed, 24 Aug 2022, Hans de Goede <hdegoede@redhat.com> 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@redhat.com> >> --- >> 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; >
On Wed, 24 Aug 2022, Hans de Goede <hdegoede@redhat.com> wrote: > Hi, > > On 8/24/22 14:47, Jani Nikula wrote: >> On Wed, 24 Aug 2022, Hans de Goede <hdegoede@redhat.com> 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@redhat.com> >>> --- >>> 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; >> >
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(); 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;
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@redhat.com> --- 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(+)