drm/i915/dp: Fix determining SST/MST mode during MTP TU state computation

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

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index aeda59f5fa7a47dc0e5658fb0795e55dbe9d7c22..30f5636d18b7d8151389ab6cffeea9cbeafd0fc0 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -253,7 +253,7 @@ 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_dp->is_mst;
+       bool is_mst = intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST);
        int bpp_x16, slots = -EINVAL;
        int dsc_slice_count = 0;
        int max_dpt_bpp_x16;