diff options
| -rw-r--r-- | drivers/gpu/drm/drm_edid.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 3326987a988..dd35dc11ffd 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -502,6 +502,19 @@ static struct drm_display_mode *drm_find_dmt(struct drm_device *dev, } return mode; } + +/* + * 0 is reserved. The spec says 0x01 fill for unused timings. Some old + * monitors fill with ascii space (0x20) instead. + */ +static int +bad_std_timing(u8 a, u8 b) +{ + return (a == 0x00 && b == 0x00) || + (a == 0x01 && b == 0x01) || + (a == 0x20 && b == 0x20); +} + /** * drm_mode_std - convert standard mode info (width, height, refresh) into mode * @t: standard timing params @@ -525,6 +538,9 @@ struct drm_display_mode *drm_mode_std(struct drm_device *dev, unsigned vfreq = (t->vfreq_aspect & EDID_TIMING_VFREQ_MASK) >> EDID_TIMING_VFREQ_SHIFT; + if (bad_std_timing(t->hsize, t->vfreq_aspect)) + return NULL; + /* According to the EDID spec, the hdisplay = hsize * 8 + 248 */ hsize = t->hsize * 8 + 248; /* vrefresh_rate = vfreq + 60 */ |