From 2e9fda82c98b1e417b90ff5a2f8b8b96cac06fc5 Mon Sep 17 00:00:00 2001 From: "Tianci.Yin" Date: Tue, 8 Mar 2022 13:45:45 +0800 Subject: [PATCH] drm/amd/display: fix dp kvm can't light up [why] The DP KVM failed to light up, since the lttpr_mode is not reset to default value when failed to read LTTPR capabilities, and the variable max_link_rate retains a initial value zero, this cause variable link_rate be assigned to an error value zero, consquently pixel_clock get wrong value zero, and kvm can't light up. [how] Reset lttpr_mode to default value when failed to read LTTPR capabilities, so that the link_rate fallbacks to the minimum rate that supported by link encoder and sink. Reviewed-by: Harry Wentland Signed-off-by: Tianci.Yin Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 1 + 1 file changed, 1 insertion(+) 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 7d88165..c35d55f 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 @@ -5110,6 +5110,7 @@ bool dp_retrieve_lttpr_cap(struct dc_link *link) sizeof(lttpr_dpcd_data)); if (status != DC_OK) { DC_LOG_DP2("%s: Read LTTPR caps data failed.\n", __func__); + link->lttpr_mode = LTTPR_MODE_NON_LTTPR; return false; } -- 2.7.4