From: Tianci.Yin Date: Tue, 8 Mar 2022 05:45:45 +0000 (+0800) Subject: drm/amd/display: fix dp kvm can't light up X-Git-Tag: v5.18-rc1~134^2^2~37 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2e9fda82c98b1e417b90ff5a2f8b8b96cac06fc5;p=thirdparty%2Fkernel%2Flinux.git 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 --- 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 7d88165e8fa2b..c35d55fe41aba 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; }