From: Taimur Hassan <syed.hassan@xxxxxxx>
[Why]
Maximum resolution is 1440*900 when connecting to FHD monitor via some DP-VGA
dongles. The display EDID reading fails over AUX/I2C via DP->VGA dongle, and
this leads to the maximum resolution 1920*1080 cannot be obtained from EDID.
[How]
Provide a workaround for some legacy DP-VGA dongles with a longer aux delay.
Signed-off-by: Taimur Hassan <syed.hassan@xxxxxxx>
Reviewed-by: Wenjing Liu <Wenjing.Liu@xxxxxxx>
Acked-by: Anson Jacob <Anson.Jacob@xxxxxxx>
---
drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
index 26f3d5dd0453..ae6484ab567b 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
@@ -39,12 +39,14 @@
#define DC_LOGGER_INIT(logger)
-/*DP to Dual link DVI converter*/
+static const uint8_t DP_VGA_DONGLE_BRANCH_DEV_NAME[] = "DpVga";
+/* DP to Dual link DVI converter */
static const uint8_t DP_DVI_CONVERTER_ID_4[] = "m2DVIa";
static const uint8_t DP_DVI_CONVERTER_ID_5[] = "3393N2";
#define AUX_POWER_UP_WA_DELAY 500
#define I2C_OVER_AUX_DEFER_WA_DELAY 70
+#define DPVGA_DONGLE_AUX_DEFER_WA_DELAY 40
#define I2C_OVER_AUX_DEFER_WA_DELAY_1MS 1
/* CV smart dongle slave address for retrieving supported HDTV modes*/
@@ -292,6 +294,15 @@ static uint32_t defer_delay_converter_wa(
{
struct dc_link *link = ddc->link;
+ if (link->dpcd_caps.dongle_type == DISPLAY_DONGLE_DP_VGA_CONVERTER &&
+ link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_0080E1 &&
+ !memcmp(link->dpcd_caps.branch_dev_name,
+ DP_VGA_DONGLE_BRANCH_DEV_NAME,
+ sizeof(link->dpcd_caps.branch_dev_name)))
+
+ return defer_delay > DPVGA_DONGLE_AUX_DEFER_WA_DELAY ?
+ defer_delay : DPVGA_DONGLE_AUX_DEFER_WA_DELAY;
+
if (link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_0080E1 &&
!memcmp(link->dpcd_caps.branch_dev_name,
DP_DVI_CONVERTER_ID_4,
--
2.25.1
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