[Intel-gfx] [PATCH v2] drm/i915: Allow panel fixed modes to have differing sync polarities

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Apparently some panels declare multiple modes with random
sync polarities. Seems a bit weird, but looks like Windows/GOP
doesn't care, so let follow suit and accept alternate fixed
modes regardless of their sync polarities.

v2: Don't pollute the DRM_ namespace with a define (Jani)

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6968
Acked-by: Jani Nikula <jani.nikula at intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_panel.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
index 2b4b359b8342..69ce77711b7c 100644
--- a/drivers/gpu/drm/i915/display/intel_panel.c
+++ b/drivers/gpu/drm/i915/display/intel_panel.c
@@ -85,9 +85,10 @@ static bool is_alt_drrs_mode(const struct drm_display_mode *mode,
 static bool is_alt_fixed_mode(const struct drm_display_mode *mode,
 			      const struct drm_display_mode *preferred_mode)
 {
-	return drm_mode_match(mode, preferred_mode,
-			      DRM_MODE_MATCH_FLAGS |
-			      DRM_MODE_MATCH_3D_FLAGS) &&
+	u32 sync_flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_NHSYNC |
+		DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_NVSYNC;
+
+	return (mode->flags & ~sync_flags) == (preferred_mode->flags & ~sync_flags) &&
 		mode->hdisplay == preferred_mode->hdisplay &&
 		mode->vdisplay == preferred_mode->vdisplay;
 }
-- 
2.35.1