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. 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