From: Yongqiang Sun <[email protected]> Some DP panel not detected intermittently due to read dpcd caps failed when doing hot plug. [root cause] DC_HPD_CONNECT_INT_DELAY is set to 0, not delay after HPD toggle and read dpcd data, while some panel need 4ms defer to read. [solution] Add a retry when read failed.
Signed-off-by: Yongqiang Sun <[email protected]> Reviewed-by: Tony Cheng <[email protected]> Acked-by: Harry Wentland <[email protected]> --- drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c index 3b5053570229..b86325bb636f 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c @@ -2278,6 +2278,8 @@ static bool retrieve_link_cap(struct dc_link *link) union edp_configuration_cap edp_config_cap; union dp_downstream_port_present ds_port = { 0 }; enum dc_status status = DC_ERROR_UNEXPECTED; + uint32_t read_dpcd_retry_cnt = 3; + int i; memset(dpcd_data, '\0', sizeof(dpcd_data)); memset(&down_strm_port_count, @@ -2285,11 +2287,15 @@ static bool retrieve_link_cap(struct dc_link *link) memset(&edp_config_cap, '\0', sizeof(union edp_configuration_cap)); - status = core_link_read_dpcd( - link, - DP_DPCD_REV, - dpcd_data, - sizeof(dpcd_data)); + for (i = 0; i < read_dpcd_retry_cnt; i++) { + status = core_link_read_dpcd( + link, + DP_DPCD_REV, + dpcd_data, + sizeof(dpcd_data)); + if (status == DC_OK) + break; + } if (status != DC_OK) { dm_error("%s: Read dpcd data failed.\n", __func__); -- 2.14.1 _______________________________________________ amd-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/amd-gfx
