[PATCH] fbdev: make the best-fit section of fb_find_mode return the closest matching mode
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From: Michal Januszewski <spock@gentoo.org>
Date: 2008-02-10 18:47:21
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Subsystem:
framebuffer layer, the rest · Maintainers:
Helge Deller, Linus Torvalds
From: Michal Januszewski <spock@gentoo.org> Currently, if a perfect match in terms of resolution is not found, fb_find_mode() only looks for a best-fit mode among modes with a higher resolution than the one requested. Thus, if the user requests a resolution higher than the largest supported one, they are dropped to the default mode (usually a low resolution one). Change this behaviour so that all valid video modes are considered when looking for a best-fit mode, while still preferring modes with a higher resolution. Signed-off-by: Michal Januszewski <spock@gentoo.org> ---
diff --git a/drivers/video/modedb.c b/drivers/video/modedb.c
index 08d0725..0b6a45f 100644
--- a/drivers/video/modedb.c
+++ b/drivers/video/modedb.c@@ -522,7 +522,7 @@ int fb_find_mode(struct fb_var_screeninfo *var, int res_specified = 0, bpp_specified = 0, refresh_specified = 0; unsigned int xres = 0, yres = 0, bpp = default_bpp, refresh = 0; int yres_specified = 0, cvt = 0, rb = 0, interlace = 0, margins = 0; - u32 best, diff; + u32 best, diff, tdiff; for (i = namelen-1; i >= 0; i--) { switch (name[i]) {
@@ -651,19 +651,27 @@ done: return (refresh_specified) ? 2 : 1; } - diff = xres + yres; + diff = 2 * (xres + yres); best = -1; DPRINTK("Trying best-fit modes\n"); for (i = 0; i < dbsize; i++) { - if (xres <= db[i].xres && yres <= db[i].yres) { DPRINTK("Trying %ix%i\n", db[i].xres, db[i].yres); if (!fb_try_mode(var, info, &db[i], bpp)) { - if (diff > (db[i].xres - xres) + (db[i].yres - yres)) { - diff = (db[i].xres - xres) + (db[i].yres - yres); - best = i; - } + tdiff = abs(db[i].xres - xres) + + abs(db[i].yres - yres); + + /* + * Penalize modes with resolutions smaller + * than requested. + */ + if (xres > db[i].xres || yres > db[i].yres) + tdiff += xres + yres; + + if (diff > tdiff) { + diff = tdiff; + best = i; + } } - } } if (best != -1) { fb_try_mode(var, info, &db[best], bpp); -------------------------------------------------------------------------
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