drm/i915: Honor sync polarity from VBT panel timing descriptors

I'm actually kind of shocked that it works at all otherwise.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 4c748d8f73d6..96f75d7f6633 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -95,6 +95,16 @@ fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
         panel_fixed_mode->clock = dvo_timing->clock * 10;
         panel_fixed_mode->type = DRM_MODE_TYPE_PREFERRED;
 
+        if (dvo_timing->hsync_positive)
+                panel_fixed_mode->flags |= DRM_MODE_FLAG_PHSYNC;
+        else
+                panel_fixed_mode->flags |= DRM_MODE_FLAG_NHSYNC;
+
+        if (dvo_timing->vsync_positive)
+                panel_fixed_mode->flags |= DRM_MODE_FLAG_PVSYNC;
+        else
+                panel_fixed_mode->flags |= DRM_MODE_FLAG_NVSYNC;
+
         /* Some VBTs have bogus h/vtotal values */
         if (panel_fixed_mode->hsync_end > panel_fixed_mode->htotal)
                 panel_fixed_mode->htotal = panel_fixed_mode->hsync_end + 1;