commit 732b87a409667a370b87955c518e5d004de740b5 upstream.

Determining the SST/MST mode during state computation must be done based on the output type stored in the CRTC state, which in turn is set once based on the modeset connector's SST vs. MST type and will not change as long as the connector is using the CRTC. OTOH the MST mode indicated by the given connector's intel_dp::is_mst flag can change independently of the above output type, based on what sink is at any moment plugged to the connector.

Fix the state computation accordingly.

Cc: Jani Nikula jani.nikula@intel.com Fixes: f6971d7427c2 ("drm/i915/mst: adapt intel_dp_mtp_tu_compute_config() for 128b/132b SST") Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4607 Reviewed-by: Jani Nikula jani.nikula@intel.com Signed-off-by: Imre Deak imre.deak@intel.com Link: https://lore.kernel.org/r/20250507151953.251846-1-imre.deak@intel.com (cherry picked from commit 0f45696ddb2b901fbf15cb8d2e89767be481d59f) Signed-off-by: Jani Nikula jani.nikula@intel.com (cherry picked from commit 732b87a409667a370b87955c518e5d004de740b5) References: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14218 [Rebased on v6.14.8 and added References link. (Imre)] Signed-off-by: Imre Deak imre.deak@intel.com --- drivers/gpu/drm/i915/display/intel_dp_mst.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c index 86d6185fda50a..8a6135b179d3b 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c @@ -221,6 +221,7 @@ int intel_dp_mtp_tu_compute_config(struct intel_dp *intel_dp, to_intel_connector(conn_state->connector); const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode; + bool is_mst = intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST); fixed20_12 pbn_div; int bpp, slots = -EINVAL; int dsc_slice_count = 0; @@ -271,7 +272,7 @@ int intel_dp_mtp_tu_compute_config(struct intel_dp *intel_dp, link_bpp_x16, &crtc_state->dp_m_n);

- if (intel_dp->is_mst) { + if (is_mst) { int remote_bw_overhead; int remote_tu; fixed20_12 pbn;