Re: [PATCH 1/4] fbdev: make fb_find_mode look for a mode with the highest refresh rate

On Sat, 2007-06-23 at 11:04 -0700, Andrew Morton wrote:

On Sat, 23 Jun 2007 12:50:46 +0200 Michal Januszewski [off-list ref] wrote:

quoted

If the refresh rate hasn't been explicitly specified, fd_find_mode
currently returns the first mode with the requested resolution. Change
it so that it returns a mode with the requested resolution and the
highest refresh rate.

Also export fb_destroy_modelist, which is used in uvesafb.

Signed-off-by: Michal Januszewski <spock@gentoo.org>
---
drivers/video/modedb.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/video/modedb.c b/drivers/video/modedb.c
index 3741ad7..98ee77b 100644
--- a/drivers/video/modedb.c
+++ b/drivers/video/modedb.c

@@ -606,16 +606,18 @@ done:
 	DPRINTK("Trying specified video mode%s %ix%i\n",
 	    refresh_specified ? "" : " (ignoring refresh rate)", xres, yres);
 
+	if (!refresh_specified)
+		refresh = 200;
 	diff = refresh;
 	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)
+				if (refresh_specified && db[i].refresh == refresh)
 					return 1;
 				else {
-					if(diff > abs(db[i].refresh - refresh)) {
+					if (diff > abs(db[i].refresh - refresh)) {
 						diff = abs(db[i].refresh - refresh);
 						best = i;
 					}

@@ -938,6 +940,7 @@ void fb_destroy_modelist(struct list_head *head)
 		kfree(pos);
 	}
 }
+EXPORT_SYMBOL_GPL(fb_destroy_modelist);
 

fbdev ignoramus asks: isn't this pretty risky?  People who were previously
relying upon (or at least using) the kernel's default resolution will find
their displays coming up in a quite different resolution.

It's only the refresh rate that will change.  The current behavior is
that a user can get near random results in terms of the vertical refresh
rates.  At least with this patch, we know what we get.

This change seems to be quite unrelated to the uvesafb stuff and should be
in a separate patch from the export, which _is_ uvesafb-related.  I think. 
If that's wrong then the changelog could do with some attention.

Tony


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