On 8/24/2025 3:01 PM, Antheas Kapenekakis wrote:
Currently, the brightness quirk is limited to minimum brightness only.
Refactor it to a structure, so that more quirks can be added in the
future. Reserve 0 value for "no quirk", and use u16 to allow minimum
brightness up to 255.
Signed-off-by: Antheas Kapenekakis <l...@antheas.dev>
'Conceptually' this idea makes sense to me if we do end up having a need
for new types of quirks besides minimum brightness.
---
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 ++++--
.../link/protocols/link_edp_panel_control.c | 2 +-
drivers/gpu/drm/drm_panel_backlight_quirks.c | 41 ++++++++++---------
include/drm/drm_utils.h | 7 +++-
4 files changed, 36 insertions(+), 26 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index cd0e2976e268..4ad80ae615a2 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3612,11 +3612,11 @@ static struct drm_mode_config_helper_funcs
amdgpu_dm_mode_config_helperfuncs = {
static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
{
+ const struct drm_panel_backlight_quirk *panel_backlight_quirk;
struct amdgpu_dm_backlight_caps *caps;
struct drm_connector *conn_base;
struct amdgpu_device *adev;
struct drm_luminance_range_info *luminance_range;
- int min_input_signal_override;
if (aconnector->bl_idx == -1 ||
aconnector->dc_link->connector_signal != SIGNAL_TYPE_EDP)
@@ -3656,9 +3656,13 @@ static void update_connector_ext_caps(struct
amdgpu_dm_connector *aconnector)
else
caps->aux_min_input_signal = 1;
- min_input_signal_override = drm_get_panel_min_brightness_quirk(aconnector->drm_edid);
- if (min_input_signal_override >= 0)
- caps->min_input_signal = min_input_signal_override;
+ panel_backlight_quirk =
+ drm_get_panel_backlight_quirk(aconnector->drm_edid);
+ if (!IS_ERR_OR_NULL(panel_backlight_quirk)) {
+ if (panel_backlight_quirk->min_brightness)
+ caps->min_input_signal =
+ panel_backlight_quirk->min_brightness - 1;
+ }
}
DEFINE_FREE(sink_release, struct dc_sink *, if (_T) dc_sink_release(_T))
diff --git
a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
index e7927b8f5ba3..a1f37267b85e 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
@@ -201,7 +201,7 @@ bool edp_set_backlight_level_nits(struct dc_link *link,
return false;
} else if (link->backlight_control_type == BACKLIGHT_CONTROL_AMD_AUX) {
struct dpcd_source_backlight_set dpcd_backlight_set;
- *(uint32_t *)&dpcd_backlight_set.backlight_level_millinits =
backlight_millinits;
+ *(uint32_t *)&dpcd_backlight_set.backlight_level_millinits =
backlight_millinits | 3;
This seems like a spurious change that was perhaps meant to be tied to a
new conceptual quirk.
*(uint16_t *)&dpcd_backlight_set.backlight_transition_time_ms =
(uint16_t)transition_time_in_ms;
uint8_t backlight_control = isHDR ? 1 : 0;
diff --git a/drivers/gpu/drm/drm_panel_backlight_quirks.c
b/drivers/gpu/drm/drm_panel_backlight_quirks.c
index b38b33e26ea5..702726c20ccc 100644
--- a/drivers/gpu/drm/drm_panel_backlight_quirks.c
+++ b/drivers/gpu/drm/drm_panel_backlight_quirks.c
@@ -8,23 +8,23 @@
#include <drm/drm_edid.h>
#include <drm/drm_utils.h>
-struct drm_panel_min_backlight_quirk {
+struct drm_get_panel_backlight_quirk {
struct {
enum dmi_field field;
const char * const value;
} dmi_match;
struct drm_edid_ident ident;
- u8 min_brightness;
+ struct drm_panel_backlight_quirk quirk;
};
-static const struct drm_panel_min_backlight_quirk drm_panel_min_backlight_quirks[] = {
+static const struct drm_get_panel_backlight_quirk
drm_panel_min_backlight_quirks[] = {
/* 13 inch matte panel */
{
.dmi_match.field = DMI_BOARD_VENDOR,
.dmi_match.value = "Framework",
.ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E',
0x0bca),
.ident.name = "NE135FBM-N41",
- .min_brightness = 0,
+ .quirk = { .min_brightness = 1, },
},
/* 13 inch glossy panel */
{
@@ -32,7 +32,7 @@ static const struct drm_panel_min_backlight_quirk
drm_panel_min_backlight_quirks
.dmi_match.value = "Framework",
.ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E',
0x095f),
.ident.name = "NE135FBM-N41",
- .min_brightness = 0,
+ .quirk = { .min_brightness = 1, },
},
/* 13 inch 2.8k panel */
{
@@ -40,12 +40,13 @@ static const struct drm_panel_min_backlight_quirk
drm_panel_min_backlight_quirks
.dmi_match.value = "Framework",
.ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E',
0x0cb4),
.ident.name = "NE135A1M-NY1",
- .min_brightness = 0,
+ .quirk = { .min_brightness = 1, },
},
};
-static bool drm_panel_min_backlight_quirk_matches(const struct drm_panel_min_backlight_quirk *quirk,
- const struct drm_edid *edid)
+static bool drm_panel_min_backlight_quirk_matches(
+ const struct drm_get_panel_backlight_quirk *quirk,
+ const struct drm_edid *edid)
{
if (!dmi_match(quirk->dmi_match.field, quirk->dmi_match.value))
return false;
@@ -57,39 +58,39 @@ static bool drm_panel_min_backlight_quirk_matches(const
struct drm_panel_min_bac
}
/**
- * drm_get_panel_min_brightness_quirk - Get minimum supported brightness level
for a panel.
+ * drm_get_panel_backlight_quirk - Get backlight quirks for a panel
* @edid: EDID of the panel to check
*
* This function checks for platform specific (e.g. DMI based) quirks
* providing info on the minimum backlight brightness for systems where this
- * cannot be probed correctly from the hard-/firm-ware.
+ * cannot be probed correctly from the hard-/firm-ware and other sources.
*
* Returns:
- * A negative error value or
- * an override value in the range [0, 255] representing 0-100% to be scaled to
- * the drivers target range.
+ * a drm_panel_backlight_quirk struct if a quirk was found, otherwise an
+ * error pointer.
*/
-int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid)
+const struct drm_panel_backlight_quirk *
+drm_get_panel_backlight_quirk(const struct drm_edid *edid)
{
- const struct drm_panel_min_backlight_quirk *quirk;
+ const struct drm_get_panel_backlight_quirk *quirk;
size_t i;
if (!IS_ENABLED(CONFIG_DMI))
- return -ENODATA;
+ return ERR_PTR(-ENODATA);
if (!edid)
- return -EINVAL;
+ return ERR_PTR(-EINVAL);
for (i = 0; i < ARRAY_SIZE(drm_panel_min_backlight_quirks); i++) {
quirk = &drm_panel_min_backlight_quirks[i];
if (drm_panel_min_backlight_quirk_matches(quirk, edid))
- return quirk->min_brightness;
+ return &quirk->quirk;
}
- return -ENODATA;
+ return ERR_PTR(-ENODATA);
}
-EXPORT_SYMBOL(drm_get_panel_min_brightness_quirk);
+EXPORT_SYMBOL(drm_get_panel_backlight_quirk);
MODULE_DESCRIPTION("Quirks for panel backlight overrides");
MODULE_LICENSE("GPL");
diff --git a/include/drm/drm_utils.h b/include/drm/drm_utils.h
index 15fa9b6865f4..82eeee4a58ab 100644
--- a/include/drm/drm_utils.h
+++ b/include/drm/drm_utils.h
@@ -16,7 +16,12 @@ struct drm_edid;
int drm_get_panel_orientation_quirk(int width, int height);
-int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid);
+struct drm_panel_backlight_quirk {
+ u16 min_brightness;
+};
+
+const struct drm_panel_backlight_quirk *
+drm_get_panel_backlight_quirk(const struct drm_edid *edid);
signed long drm_timeout_abs_to_jiffies(int64_t timeout_nsec);
