Thread (6 messages) 6 messages, 3 authors, 2007-08-29

[PATCH] fbdev: find mode with the highest/safest refresh rate in fb_find_mode()

flat view
DORMANTno replies

From: Michal Januszewski <spock@gentoo.org>
Date: 2007-08-29 22:51:18
Also in: lkml
Subsystem: framebuffer layer, the rest · Maintainers: Helge Deller, Linus Torvalds

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>
---
diff --git a/drivers/video/modedb.c b/drivers/video/modedb.c
index 3741ad7..9598c46 100644
--- a/drivers/video/modedb.c
+++ b/drivers/video/modedb.c
@@ -606,26 +606,43 @@ done:
 	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;


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help