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authorAdam Jackson <ajax@redhat.com>2009-09-23 17:30:58 -0400
committerDave Airlie <airlied@redhat.com>2009-09-24 09:46:04 +1000
commit23425caeebc2e06629ef04f6197543cfe3f7d7b2 (patch)
tree5f5a5807b027283b90405682eb9bf58d54ea14ae /drivers/gpu/drm
parent083ae0560ab53b039aaa897b77458cbadf19050d (diff)
drm/edid: Ignore bad standard timings.
Signed-off-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm')
-rw-r--r--drivers/gpu/drm/drm_edid.c16
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 */