From fd952d436446cffdf97a61bf456a0987011e42e0 Mon Sep 17 00:00:00 2001 From: Taimur Hassan Date: Fri, 15 Jan 2021 17:34:34 -0500 Subject: drm/amd/display: Workaround for some legacy DP-VGA dongles [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 Reviewed-by: Wenjing Liu Acked-by: Anson Jacob Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- 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, -- cgit v1.2.3