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 <ball...@chromium.org>
---
.../gpu/drm/i915/display/intel_backlight.c | 6 +++++
drivers/gpu/drm/i915/display/intel_quirks.c | 27 +++++++++++++++++++
drivers/gpu/drm/i915/display/intel_quirks.h | 1 +
3 files changed, 34 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c
b/drivers/gpu/drm/i915/display/intel_backlight.c
index 2e8f17c045222..863a33245a3d7 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 hightest 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
@@ -1206,6 +1211,7 @@ static u32 get_backlight_min_vbt(struct intel_connector
*connector)
connector->panel.vbt.backlight.min_brightness, min);
}
+
/* vbt value is a coefficient in range [0..255] */
return scale(min, 0, 255, 0, panel->backlight.pwm_level_max);
}
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);
--
2.41.0.162.gfafddb0af9-goog
