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drm/amd/display: Adding support for VESA SCR

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[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.Koo@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Iswara Nagulendran <Iswara.Nagulendran@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Iswara Nagulendran 2023-03-16 16:29:06 -04:00 committed by Alex Deucher
parent e3416e872f
commit 4d5f872dbc
4 changed files with 43 additions and 5 deletions
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7
drivers/gpu/drm/amd/display/dc/dc_dp_types.h
View File

@ -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;

9
drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
View File

@ -1450,7 +1450,8 @@ 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;
@ -1459,6 +1460,12 @@ 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;
}

29
drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
View File

@ -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;
}

3
include/drm/display/drm_dp.h
View File

@ -983,6 +983,7 @@
#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)
@ -1008,6 +1009,7 @@
# 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
@ -1032,6 +1034,7 @@
#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 */