drm: Add the basic check for the detailed timing in EDID

Sometimes we will get the incorrect display modeline when parsing the detailed
timing in EDID. For example:
   >hsync/vsync width is zero
   >sync is beyond the blank.

So add the basic check for the detailed timing in EDID to avoid the incorrect
display modeline.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 3c0d2b3..cea665d 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -626,6 +626,12 @@ static struct drm_display_mode *drm_mode_detailed(struct drm_device *dev,
                return NULL;
        }
 
+       /* it is incorrect if hsync/vsync width is zero */
+       if (!hsync_pulse_width || !vsync_pulse_width) {
+               DRM_DEBUG_KMS("Incorrect Detailed timing. "
+                               "Wrong Hsync/Vsync pulse width\n");
+               return NULL;
+       }
        mode = drm_mode_create(dev);
        if (!mode)
                return NULL;
@@ -647,6 +653,15 @@ static struct drm_display_mode *drm_mode_detailed(struct drm_device *dev,
        mode->vsync_end = mode->vsync_start + vsync_pulse_width;
        mode->vtotal = mode->vdisplay + vblank;
 
+       /* perform the basic check for the detailed timing */
+       if (mode->hsync_end > mode->htotal ||
+               mode->vsync_end > mode->vtotal) {
+               drm_mode_destroy(dev, mode);
+               DRM_DEBUG_KMS("Incorrect detailed timing. "
+                               "Sync is beyond the blank.\n");
+               return NULL;
+       }
+
        drm_mode_set_name(mode);
 
        if (pt->misc & DRM_EDID_PT_INTERLACED)