On Tue, 08 Aug 2023, Allen Ballway <ballway@xxxxxxxxxxxx> wrote: > Cybernet T10C cannot be dimmed without the backlight strobing. Create a > new quirk to lock the minimum brightness to the highest supported value. > This aligns the device with its behavior on Windows, which will not > lower the brightness below maximum. Noting here for the benefit of others, it's possible to make the brightness work [1], now we "just" need to figure out how to do that nicely. So we should drop this patch. BR, Jani. [1] https://gitlab.freedesktop.org/drm/intel/-/issues/8187#note_2072633 > > Signed-off-by: Allen Ballway <ballway@xxxxxxxxxxxx> > --- > V2 -> V3: Fix typo. > V1 -> V2: Fix style issue. > > .../gpu/drm/i915/display/intel_backlight.c | 5 ++++ > drivers/gpu/drm/i915/display/intel_quirks.c | 27 +++++++++++++++++++ > drivers/gpu/drm/i915/display/intel_quirks.h | 1 + > 3 files changed, 33 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c > index 2e8f17c045222..f015563d3ebd5 100644 > --- a/drivers/gpu/drm/i915/display/intel_backlight.c > +++ b/drivers/gpu/drm/i915/display/intel_backlight.c > @@ -1192,6 +1192,11 @@ static u32 get_backlight_min_vbt(struct intel_connector *connector) > > drm_WARN_ON(&i915->drm, panel->backlight.pwm_level_max == 0); > > + if (intel_has_quirk(i915, QUIRK_NO_DIM)) { > + /* Cannot dim backlight, set minimum to highest value */ > + return panel->backlight.pwm_level_max - 1; > + } > + > /* > * XXX: If the vbt value is 255, it makes min equal to max, which leads > * to problems. There are such machines out there. Either our > diff --git a/drivers/gpu/drm/i915/display/intel_quirks.c b/drivers/gpu/drm/i915/display/intel_quirks.c > index a280448df771a..910c95840a539 100644 > --- a/drivers/gpu/drm/i915/display/intel_quirks.c > +++ b/drivers/gpu/drm/i915/display/intel_quirks.c > @@ -65,6 +65,12 @@ static void quirk_no_pps_backlight_power_hook(struct drm_i915_private *i915) > drm_info(&i915->drm, "Applying no pps backlight power quirk\n"); > } > > +static void quirk_no_dim(struct drm_i915_private *i915) > +{ > + intel_set_quirk(i915, QUIRK_NO_DIM); > + drm_info(&i915->drm, "Applying no dim quirk\n"); > +} > + > struct intel_quirk { > int device; > int subsystem_vendor; > @@ -90,6 +96,12 @@ static int intel_dmi_no_pps_backlight(const struct dmi_system_id *id) > return 1; > } > > +static int intel_dmi_no_dim(const struct dmi_system_id *id) > +{ > + DRM_INFO("No dimming allowed on %s\n", id->ident); > + return 1; > +} > + > static const struct intel_dmi_quirk intel_dmi_quirks[] = { > { > .dmi_id_list = &(const struct dmi_system_id[]) { > @@ -136,6 +148,20 @@ static const struct intel_dmi_quirk intel_dmi_quirks[] = { > }, > .hook = quirk_no_pps_backlight_power_hook, > }, > + { > + .dmi_id_list = &(const struct dmi_system_id[]) { > + { > + .callback = intel_dmi_no_dim, > + .ident = "Cybernet T10C Tablet", > + .matches = {DMI_EXACT_MATCH(DMI_BOARD_VENDOR, > + "Cybernet Manufacturing Inc."), > + DMI_EXACT_MATCH(DMI_BOARD_NAME, "T10C Tablet"), > + }, > + }, > + { } > + }, > + .hook = quirk_no_dim, > + }, > }; > > static struct intel_quirk intel_quirks[] = { > @@ -218,6 +244,7 @@ void intel_init_quirks(struct drm_i915_private *i915) > q->subsystem_device == PCI_ANY_ID)) > q->hook(i915); > } > + > for (i = 0; i < ARRAY_SIZE(intel_dmi_quirks); i++) { > if (dmi_check_system(*intel_dmi_quirks[i].dmi_id_list) != 0) > intel_dmi_quirks[i].hook(i915); > diff --git a/drivers/gpu/drm/i915/display/intel_quirks.h b/drivers/gpu/drm/i915/display/intel_quirks.h > index 10a4d163149fd..b41c7bbf0a5e3 100644 > --- a/drivers/gpu/drm/i915/display/intel_quirks.h > +++ b/drivers/gpu/drm/i915/display/intel_quirks.h > @@ -17,6 +17,7 @@ enum intel_quirk_id { > QUIRK_INVERT_BRIGHTNESS, > QUIRK_LVDS_SSC_DISABLE, > QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK, > + QUIRK_NO_DIM, > }; > > void intel_init_quirks(struct drm_i915_private *i915); > -- > 2.41.0.255.g8b1d071c50-goog > -- Jani Nikula, Intel Open Source Graphics Center
