.../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(+)
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@chromium.org>
---
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..049e95105e8b6 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
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
On Thu, Jun 22, 2023 at 05:28:15PM +0000, Allen Ballway wrote:
> --- 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 */
Typo: s/hightest/highest/
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@chromium.org>
---
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
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@chromium.org>
---
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
On Tue, 08 Aug 2023, Allen Ballway <ballway@chromium.org> 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@chromium.org>
> ---
> 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
© 2016 - 2026 Red Hat, Inc.