fbdev: make the best-fit section of fb_find_mode return the closest matching mode (6b745b6f) · Commits · 戴 / test

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> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/modedb.c

+16 −8

Original line number	Diff line number	Diff line
		@@ -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]) {
		@@ -651,20 +651,28 @@ 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);
		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);
		return 5;

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