drm/i915: Disable port sync when bigjoiner is used

commit 0653d50 upstream.

The current modeset sequence can't handle port sync and bigjoiner
at the same time. Refuse port sync when bigjoiner is needed,
at least until we fix the modeset sequence.

v2: Add a FIXME (Vandite)

Cc: [email protected]
Tested-by: Vidya Srinivas <[email protected]>
Reviewed-by: Vandita Kulkarni <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Ville Syrjälä <[email protected]>
(cherry picked from commit b37e134)
Signed-off-by: Rodrigo Vivi <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: vsyrjala

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -4111,7 +4111,12 @@ static bool m_n_equal(const struct intel_link_m_n *m_n_1,
 static bool crtcs_port_sync_compatible(const struct intel_crtc_state *crtc_state1,
 				       const struct intel_crtc_state *crtc_state2)
 {
+	/*
+	 * FIXME the modeset sequence is currently wrong and
+	 * can't deal with bigjoiner + port sync at the same time.
+	 */
 	return crtc_state1->hw.active && crtc_state2->hw.active &&
+		!crtc_state1->bigjoiner_pipes && !crtc_state2->bigjoiner_pipes &&
 		crtc_state1->output_types == crtc_state2->output_types &&
 		crtc_state1->output_format == crtc_state2->output_format &&
 		crtc_state1->lane_count == crtc_state2->lane_count &&