drm/i915/mst: Reject modes that require the bigjoiner

commit dd7eb65c493615fda7d459501c3d4a46e00ea5ba upstream.

We have no bigjoiner support in the MST code, so .mode_valid()
pretending otherwise is just going to result black screens for
users. Reject any mode that needs the joiner.

Cc: stable@vger.kernel.org
Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Fixes: d51f25eb479a ("drm/i915: Add DSC support to MST path")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127145028.4899-3-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit 9c058492b16f90bb772cb0dad567e8acc68e155d)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index ccea5ea..7a3d024 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -955,6 +955,10 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector *connector,
        if (intel_dp_need_bigjoiner(intel_dp, mode->hdisplay, target_clock)) {
                bigjoiner = true;
                max_dotclk *= 2;
+
+               /* TODO: add support for bigjoiner */
+               *status = MODE_CLOCK_HIGH;
+               return 0;
        }
 
        if (DISPLAY_VER(dev_priv) >= 10 &&