[PATCH 6.17.y 2/2] drm/i915/dp_mst: Disable Panel Replay

[Sasha Levin <sashal@kernel.org>]

From: Imre Deak <imre.deak@intel.com>

[ Upstream commit f2687d3cc9f905505d7b510c50970176115066a2 ]

Disable Panel Replay on MST links until it's properly implemented. For
instance the required VSC SDP is not programmed on MST and FEC is not
enabled if Panel Replay is enabled.

Fixes: 3257e55d3ea7 ("drm/i915/panelreplay: enable/disable panel replay")
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15174
Cc: Jouni Högander <jouni.hogander@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: stable@vger.kernel.org # v6.8+
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patch.msgid.link/20251107124141.911895-1-imre.deak@intel.com
(cherry picked from commit e109f644b871df8440c886a69cdce971ed533088)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/i915/display/intel_psr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 88531c9be22cb..42e1f044f77f5 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -602,6 +602,10 @@ static void _panel_replay_init_dpcd(struct intel_dp *intel_dp)
 	struct intel_display *display = to_intel_display(intel_dp);
 	int ret;
 
+	/* TODO: Enable Panel Replay on MST once it's properly implemented. */
+	if (intel_dp->mst_detect == DRM_DP_MST)
+		return;
+
 	ret = drm_dp_dpcd_read_data(&intel_dp->aux, DP_PANEL_REPLAY_CAP_SUPPORT,
 				    &intel_dp->pr_dpcd, sizeof(intel_dp->pr_dpcd));
 	if (ret < 0)
-- 
2.51.0