[PATCH] drm/edid: compare actual vrefresh for all modes for quirks

[Alex Deucher]

The vrefresh field of the mode is 0 for most modes
fetched from the EDID (e.g., established timings).
When dealing with monitors that have a bogus preferred
mode, we may not always select the mode we want because
we compare the target refresh to the mode's vrefresh which
is 0 in a lot of cases.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/drm_edid.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 58b4882..c3095e0 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1278,7 +1278,7 @@ static u32 edid_get_quirks(struct edid *edid)
 }
 
 #define MODE_SIZE(m) ((m)->hdisplay * (m)->vdisplay)
-#define MODE_REFRESH_DIFF(m,r) (abs((m)->vrefresh - target_refresh))
+#define MODE_REFRESH_DIFF(c,t) (abs((c) - (t)))
 
 /**
  * edid_fixup_preferred - set preferred modes based on quirk list
@@ -1293,6 +1293,7 @@ static void edid_fixup_preferred(struct drm_connector *connector,
 {
 	struct drm_display_mode *t, *cur_mode, *preferred_mode;
 	int target_refresh = 0;
+	int cur_vrefresh, preferred_vrefresh;
 
 	if (list_empty(&connector->probed_modes))
 		return;
@@ -1315,10 +1316,14 @@ static void edid_fixup_preferred(struct drm_connector *connector,
 		if (MODE_SIZE(cur_mode) > MODE_SIZE(preferred_mode))
 			preferred_mode = cur_mode;
 
+		cur_vrefresh = cur_mode->vrefresh ?
+			cur_mode->vrefresh : drm_mode_vrefresh(cur_mode);
+		preferred_vrefresh = preferred_mode->vrefresh ?
+			preferred_mode->vrefresh : drm_mode_vrefresh(preferred_mode);
 		/* At a given size, try to get closest to target refresh */
 		if ((MODE_SIZE(cur_mode) == MODE_SIZE(preferred_mode)) &&
-		    MODE_REFRESH_DIFF(cur_mode, target_refresh) <
-		    MODE_REFRESH_DIFF(preferred_mode, target_refresh)) {
+		    MODE_REFRESH_DIFF(cur_vrefresh, target_refresh) <
+		    MODE_REFRESH_DIFF(preferred_vrefresh, target_refresh)) {
 			preferred_mode = cur_mode;
 		}
 	}
-- 
1.8.3.1