freebsd-dev/sys/dev/videomode/pickmode.c

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/* $NetBSD: pickmode.c,v 1.3 2011/04/09 18:22:31 jdc Exp $ */
/* $FreeBSD$ */
/*-
* Copyright (c) 2006 The NetBSD Foundation
* All rights reserved.
*
* this code was contributed to The NetBSD Foundation by Michael Lorenz
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE NETBSD FOUNDATION BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/libkern.h>
#include <dev/videomode/videomode.h>
#include "opt_videomode.h"
#ifdef PICKMODE_DEBUG
#define DPRINTF printf
#else
#define DPRINTF while (0) printf
#endif
const struct videomode *
pick_mode_by_dotclock(int width, int height, int dotclock)
{
const struct videomode *this, *best = NULL;
int i;
DPRINTF("%s: looking for %d x %d at up to %d kHz\n", __func__, width,
height, dotclock);
for (i = 0; i < videomode_count; i++) {
this = &videomode_list[i];
if ((this->hdisplay != width) || (this->vdisplay != height) ||
(this->dot_clock > dotclock))
continue;
if (best != NULL) {
if (this->dot_clock > best->dot_clock)
best = this;
} else
best = this;
}
if (best != NULL)
DPRINTF("found %s\n", best->name);
return best;
}
const struct videomode *
pick_mode_by_ref(int width, int height, int refresh)
{
const struct videomode *this, *best = NULL;
int mref, closest = 1000, i, diff;
DPRINTF("%s: looking for %d x %d at up to %d Hz\n", __func__, width,
height, refresh);
for (i = 0; i < videomode_count; i++) {
this = &videomode_list[i];
mref = this->dot_clock * 1000 / (this->htotal * this->vtotal);
diff = abs(mref - refresh);
if ((this->hdisplay != width) || (this->vdisplay != height))
continue;
DPRINTF("%s in %d hz, diff %d\n", this->name, mref, diff);
if (best != NULL) {
if (diff < closest) {
best = this;
closest = diff;
}
} else {
best = this;
closest = diff;
}
}
if (best != NULL)
DPRINTF("found %s %d\n", best->name, best->dot_clock);
return best;
}
static inline void
swap_modes(struct videomode *left, struct videomode *right)
{
struct videomode temp;
temp = *left;
*left = *right;
*right = temp;
}
/*
* Sort modes by refresh rate, aspect ratio (*), then resolution.
* Preferred mode or largest mode is first in the list and other modes
* are sorted on closest match to that mode.
* (*) Note that the aspect ratio calculation treats "close" aspect ratios
* (within 12.5%) as the same for this purpose.
*/
#define DIVIDE(x, y) (((x) + ((y) / 2)) / (y))
void
sort_modes(struct videomode *modes, struct videomode **preferred, int nmodes)
{
int aspect, refresh, hbest, vbest, abest, atemp, rbest, rtemp;
int i, j;
struct videomode *mtemp = NULL;
if (nmodes < 2)
return;
if (*preferred != NULL) {
/* Put the preferred mode first in the list */
aspect = (*preferred)->hdisplay * 100 / (*preferred)->vdisplay;
refresh = DIVIDE(DIVIDE((*preferred)->dot_clock * 1000,
(*preferred)->htotal), (*preferred)->vtotal);
if (*preferred != modes) {
swap_modes(*preferred, modes);
*preferred = modes;
}
} else {
/*
* Find the largest horizontal and vertical mode and put that
* first in the list. Preferred refresh rate is taken from
* the first mode of this size.
*/
hbest = 0;
vbest = 0;
for (i = 0; i < nmodes; i++) {
if (modes[i].hdisplay > hbest) {
hbest = modes[i].hdisplay;
vbest = modes[i].vdisplay;
mtemp = &modes[i];
} else if (modes[i].hdisplay == hbest &&
modes[i].vdisplay > vbest) {
vbest = modes[i].vdisplay;
mtemp = &modes[i];
}
}
aspect = mtemp->hdisplay * 100 / mtemp->vdisplay;
refresh = DIVIDE(DIVIDE(mtemp->dot_clock * 1000,
mtemp->htotal), mtemp->vtotal);
if (mtemp != modes)
swap_modes(mtemp, modes);
}
/* Sort other modes by refresh rate, aspect ratio, then resolution */
for (j = 1; j < nmodes - 1; j++) {
rbest = 1000;
abest = 1000;
hbest = 0;
vbest = 0;
for (i = j; i < nmodes; i++) {
rtemp = abs(refresh -
DIVIDE(DIVIDE(modes[i].dot_clock * 1000,
modes[i].htotal), modes[i].vtotal));
atemp = (modes[i].hdisplay * 100 / modes[i].vdisplay);
if (rtemp < rbest) {
rbest = rtemp;
mtemp = &modes[i];
}
if (rtemp == rbest) {
/* Treat "close" aspect ratios as identical */
if (abs(abest - atemp) > (abest / 8) &&
abs(aspect - atemp) < abs(aspect - abest)) {
abest = atemp;
mtemp = &modes[i];
}
if (atemp == abest ||
abs(abest - atemp) <= (abest / 8)) {
if (modes[i].hdisplay > hbest) {
hbest = modes[i].hdisplay;
mtemp = &modes[i];
}
if (modes[i].hdisplay == hbest &&
modes[i].vdisplay > vbest) {
vbest = modes[i].vdisplay;
mtemp = &modes[i];
}
}
}
}
if (mtemp != &modes[j])
swap_modes(mtemp, &modes[j]);
}
}