From 1c5dd170927b1aa8e3a01d43d611b840336cdaf2 Mon Sep 17 00:00:00 2001
From: Michal Januszewski <spock@gentoo.org>
Date: Tue, 16 Oct 2007 01:29:19 -0700
Subject: [PATCH] fbdev: find mode with the highest/safest refresh rate in
 fb_find_mode()

Currently, if the refresh rate is not specified, fb_find_mode() returns the
first known video mode with the requested resolution, which provides no
guarantees wrt the refresh rate.  Change this so that the mode with the
highest refresh rate is returned when the driver provides a custom video mode
database and the monitor limits, and a mode with the safe 60 Hz refresh rate
otherwise.

Signed-off-by: Michal Januszewski <spock@gentoo.org>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/video/modedb.c | 41 +++++++++++++++++++++++++++++------------
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/drivers/video/modedb.c b/drivers/video/modedb.c
index f7f9c087ad70a..03b06aa2475fd 100644
--- a/drivers/video/modedb.c
+++ b/drivers/video/modedb.c
@@ -606,26 +606,43 @@ int fb_find_mode(struct fb_var_screeninfo *var,
 	DPRINTK("Trying specified video mode%s %ix%i\n",
 	    refresh_specified ? "" : " (ignoring refresh rate)", xres, yres);
 
-	diff = refresh;
+	if (!refresh_specified) {
+		/*
+		 * If the caller has provided a custom mode database and a
+		 * valid monspecs structure, we look for the mode with the
+		 * highest refresh rate.  Otherwise we play it safe it and
+		 * try to find a mode with a refresh rate closest to the
+		 * standard 60 Hz.
+		 */
+		if (db != modedb &&
+		    info->monspecs.vfmin && info->monspecs.vfmax &&
+		    info->monspecs.hfmin && info->monspecs.hfmax &&
+		    info->monspecs.dclkmax) {
+			refresh = 1000;
+		} else {
+			refresh = 60;
+		}
+	}
+
+	diff = -1;
 	best = -1;
 	for (i = 0; i < dbsize; i++) {
-		if (name_matches(db[i], name, namelen) ||
-		    (res_specified && res_matches(db[i], xres, yres))) {
-			if(!fb_try_mode(var, info, &db[i], bpp)) {
-				if(!refresh_specified || db[i].refresh == refresh)
-					return 1;
-				else {
-					if(diff > abs(db[i].refresh - refresh)) {
-						diff = abs(db[i].refresh - refresh);
-						best = i;
-					}
+		if ((name_matches(db[i], name, namelen) ||
+		    (res_specified && res_matches(db[i], xres, yres))) &&
+		    !fb_try_mode(var, info, &db[i], bpp)) {
+			if (refresh_specified && db[i].refresh == refresh) {
+				return 1;
+			} else {
+				if (abs(db[i].refresh - refresh) < diff) {
+					diff = abs(db[i].refresh - refresh);
+					best = i;
 				}
 			}
 		}
 	}
 	if (best != -1) {
 		fb_try_mode(var, info, &db[best], bpp);
-		return 2;
+		return (refresh_specified) ? 2 : 1;
 	}
 
 	diff = xres + yres;
-- 
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