From: Iswara Nagulendran <iswara.nagulend...@amd.com>
[HOW&WHY]
Write DPCD 721 bit 7 to high, and
the appropriate luminance level
to DPCD 734-736 if bit 4 from DPCD register
734 is high, indicating that the panel
luminance control is enabled from the panel side.
Reviewed-by: Anthony Koo <anthony....@amd.com>
Acked-by: Qingqing Zhuo <qingqing.z...@amd.com>
Signed-off-by: Iswara Nagulendran <iswara.nagulend...@amd.com>
---
drivers/gpu/drm/amd/display/dc/dc_dp_types.h | 7 +++++
.../dc/link/protocols/link_dp_capability.c | 9 +++++-
.../link/protocols/link_edp_panel_control.c | 29 ++++++++++++++++---
include/drm/display/drm_dp.h | 3 ++
4 files changed, 43 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
index 49aab1924665..4a7f6497dc5a 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
@@ -566,6 +566,12 @@ struct dpcd_amd_device_id {
uint8_t dal_version_byte2;
};
+struct target_luminance_value {
+ uint8_t byte0;
+ uint8_t byte1;
+ uint8_t byte2;
+};
+
struct dpcd_source_backlight_set {
struct {
uint8_t byte0;
@@ -1225,6 +1231,7 @@ struct dpcd_caps {
union dp_main_line_channel_coding_cap channel_coding_cap;
union dp_sink_video_fallback_formats fallback_formats;
union dp_fec_capability1 fec_cap1;
+ bool panel_luminance_control;
union dp_cable_id cable_id;
uint8_t edp_rev;
union edp_alpm_caps alpm_caps;
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
index eeaceed61bc4..50327a559a47 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
@@ -1449,7 +1449,8 @@ bool read_is_mst_supported(struct dc_link *link)
*/
static bool dpcd_read_sink_ext_caps(struct dc_link *link)
{
- uint8_t dpcd_data;
+ uint8_t dpcd_data = 0;
+ uint8_t edp_general_cap2 = 0;
if (!link)
return false;
@@ -1458,6 +1459,12 @@ static bool dpcd_read_sink_ext_caps(struct dc_link *link)
return false;
link->dpcd_sink_ext_caps.raw = dpcd_data;
+
+ if (core_link_read_dpcd(link, DP_EDP_GENERAL_CAP_2, &edp_general_cap2,
1) != DC_OK)
+ return false;
+
+ link->dpcd_caps.panel_luminance_control = (edp_general_cap2 &
DP_EDP_PANEL_LUMINANCE_CONTROL_CAPABLE) != 0;
+
return true;
}
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 d895046787bc..5ab2de12ccf8 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
@@ -164,14 +164,35 @@ bool edp_set_backlight_level_nits(struct dc_link *link,
*(uint16_t *)&dpcd_backlight_set.backlight_transition_time_ms =
(uint16_t)transition_time_in_ms;
- if (core_link_write_dpcd(link, DP_SOURCE_BACKLIGHT_LEVEL,
+ if (!link->dpcd_caps.panel_luminance_control) {
+ if (core_link_write_dpcd(link, DP_SOURCE_BACKLIGHT_LEVEL,
(uint8_t *)(&dpcd_backlight_set),
sizeof(dpcd_backlight_set)) != DC_OK)
- return false;
+ return false;
- if (core_link_write_dpcd(link, DP_SOURCE_BACKLIGHT_CONTROL,
+ if (core_link_write_dpcd(link, DP_SOURCE_BACKLIGHT_CONTROL,
&backlight_control, 1) != DC_OK)
- return false;
+ return false;
+ } else {
+ const uint8_t backlight_enable =
DP_EDP_PANEL_LUMINANCE_CONTROL_ENABLE;
+ struct target_luminance_value *target_luminance = NULL;
+
+ //if target luminance value is greater than 24 bits, clip the
value to 24 bits
+ if (backlight_millinits > 0xFFFFFF)
+ backlight_millinits = 0xFFFFFF;
+
+ target_luminance = (struct target_luminance_value
*)&backlight_millinits;
+
+ if (core_link_write_dpcd(link,
DP_EDP_BACKLIGHT_MODE_SET_REGISTER,
+ &backlight_enable,
+ sizeof(backlight_enable)) != DC_OK)
+ return false;
+
+ if (core_link_write_dpcd(link,
DP_EDP_PANEL_TARGET_LUMINANCE_VALUE,
+ (uint8_t *)(target_luminance),
+ sizeof(struct target_luminance_value)) != DC_OK)
+ return false;
+ }
return true;
}
diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
index ed10e6b6f99d..f1be179c5f1f 100644
--- a/include/drm/display/drm_dp.h
+++ b/include/drm/display/drm_dp.h
@@ -973,6 +973,7 @@
#define DP_EDP_GENERAL_CAP_2 0x703
# define DP_EDP_OVERDRIVE_ENGINE_ENABLED (1 << 0)
+# define DP_EDP_PANEL_LUMINANCE_CONTROL_CAPABLE (1 << 4)
#define DP_EDP_GENERAL_CAP_3 0x704 /* eDP 1.4 */
# define DP_EDP_X_REGION_CAP_MASK (0xf << 0)
@@ -998,6 +999,7 @@
# define DP_EDP_DYNAMIC_BACKLIGHT_ENABLE (1 << 4)
# define DP_EDP_REGIONAL_BACKLIGHT_ENABLE (1 << 5)
# define DP_EDP_UPDATE_REGION_BRIGHTNESS (1 << 6) /* eDP 1.4 */
+# define DP_EDP_PANEL_LUMINANCE_CONTROL_ENABLE (1 << 7)
#define DP_EDP_BACKLIGHT_BRIGHTNESS_MSB 0x722
#define DP_EDP_BACKLIGHT_BRIGHTNESS_LSB 0x723
@@ -1022,6 +1024,7 @@
#define DP_EDP_DBC_MINIMUM_BRIGHTNESS_SET 0x732
#define DP_EDP_DBC_MAXIMUM_BRIGHTNESS_SET 0x733
+#define DP_EDP_PANEL_TARGET_LUMINANCE_VALUE 0x734
#define DP_EDP_REGIONAL_BACKLIGHT_BASE 0x740 /* eDP 1.4 */
#define DP_EDP_REGIONAL_BACKLIGHT_0 0x741 /* eDP 1.4 */
--
2.34.1
