drm/mgag200: Reject non-character-cell-aligned mode widths

Turns out 1366x768 does not in fact work on this hardware.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
index 6e84df9369a6..ad4b9010dfb0 100644
--- a/drivers/gpu/drm/mgag200/mgag200_mode.c
+++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
@@ -1526,6 +1526,11 @@ static int mga_vga_mode_valid(struct drm_connector *connector,
                 return MODE_BANDWIDTH;
         }
 
+        if ((mode->hdisplay % 8) != 0 || (mode->hsync_start % 8) != 0 ||
+            (mode->hsync_end % 8) != 0 || (mode->htotal % 8) != 0) {
+                return MODE_H_ILLEGAL;
+        }
+
         if (mode->crtc_hdisplay > 2048 || mode->crtc_hsync_start > 4096 ||
             mode->crtc_hsync_end > 4096 || mode->crtc_htotal > 4096 ||
             mode->crtc_vdisplay > 2048 || mode->crtc_vsync_start > 4096 ||