drm/amd/display: Fix FEC_READY write on DP LT

[ Upstream commit a8baec4623aedf36d50767627f6eae5ebf07c6fb ]

[Why/How]
We can miss writing FEC_READY in some cases before LT start, which
violates DP spec. Remove the condition guarding the DPCD write so that
the write happens unconditionally.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Ilya Bakoulin <ilya.bakoulin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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 f06f708ba5c877b6940571758f0907010074f40e..9bde0c8bf914a6ce48d4bcd2e7f246fbbef4f7fc 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
@@ -147,16 +147,14 @@ enum dc_status dp_set_fec_ready(struct dc_link *link, const struct link_resource
                return DC_NOT_SUPPORTED;
 
        if (ready && dp_should_enable_fec(link)) {
-               if (link->fec_state == dc_link_fec_not_ready) {
-                       fec_config = 1;
+               fec_config = 1;
 
-                       status = core_link_write_dpcd(link, DP_FEC_CONFIGURATION,
-                                       &fec_config, sizeof(fec_config));
+               status = core_link_write_dpcd(link, DP_FEC_CONFIGURATION,
+                               &fec_config, sizeof(fec_config));
 
-                       if (status == DC_OK) {
-                               link_enc->funcs->fec_set_ready(link_enc, true);
-                               link->fec_state = dc_link_fec_ready;
-                       }
+               if (status == DC_OK) {
+                       link_enc->funcs->fec_set_ready(link_enc, true);
+                       link->fec_state = dc_link_fec_ready;
                }
        } else {
                if (link->fec_state == dc_link_fec_ready) {