drm/amd/display: Don't try AUX transactions on disconnected link

[Why]
Setting link DPMS off in response to HPD disconnect creates AUX
transactions on a link that is supposed to be disconnected. This can
cause issues in some cases when the sink re-asserts HPD and expects
source to re-enable the link.

[How]
Avoid AUX transactions on disconnected link.

Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Ilya Bakoulin <Ilya.Bakoulin@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_phy.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_phy.c
index 2c73ac87cd665c0a9502315c45e2db83bae79b2d..c27ffec5d84fb2ddc54bafa1a34acb265054a197 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_phy.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_phy.c
@@ -75,7 +75,8 @@ void dp_disable_link_phy(struct dc_link *link,
        struct dc  *dc = link->ctx->dc;
 
        if (!link->wa_flags.dp_keep_receiver_powered &&
-               !link->skip_implict_edp_power_control)
+                       !link->skip_implict_edp_power_control &&
+                       link->type != dc_connection_none)
                dpcd_write_rx_power_ctrl(link, false);
 
        dc->hwss.disable_link_output(link, link_res, signal);
@@ -163,8 +164,9 @@ enum dc_status dp_set_fec_ready(struct dc_link *link, const struct link_resource
        } else {
                if (link->fec_state == dc_link_fec_ready) {
                        fec_config = 0;
-                       core_link_write_dpcd(link, DP_FEC_CONFIGURATION,
-                               &fec_config, sizeof(fec_config));
+                       if (link->type != dc_connection_none)
+                               core_link_write_dpcd(link, DP_FEC_CONFIGURATION,
+                                       &fec_config, sizeof(fec_config));
 
                        link_enc->funcs->fec_set_ready(link_enc, false);
                        link->fec_state = dc_link_fec_not_ready;