cirrusfb: check_par fixes
1. Check if virtual resolution fits into memory.
Otherwise, Linux hangs during panning.
2. When selected use all available memory to
maximize yres_virtual to speed up panning
(previously also xres_virtual was increased).
3. Simplify memory restriction calculations.
Signed-off-by: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/cirrusfb.c b/drivers/video/cirrusfb.c
index c14b243..e729fb2 100644
--- a/drivers/video/cirrusfb.c
+++ b/drivers/video/cirrusfb.c
@@ -628,27 +628,18 @@
static int cirrusfb_check_var(struct fb_var_screeninfo *var,
struct fb_info *info)
{
- int nom, den; /* translyting from pixels->bytes */
- int yres, i;
- static struct { int xres, yres; } modes[] =
- { { 1600, 1280 },
- { 1280, 1024 },
- { 1024, 768 },
- { 800, 600 },
- { 640, 480 },
- { -1, -1 } };
+ int yres;
+ /* memory size in pixels */
+ unsigned pixels = info->screen_size * 8 / var->bits_per_pixel;
switch (var->bits_per_pixel) {
case 1:
- nom = 4;
- den = 8;
+ pixels /= 4;
break; /* 8 pixel per byte, only 1/4th of mem usable */
case 8:
case 16:
case 24:
case 32:
- nom = var->bits_per_pixel / 8;
- den = 1;
break; /* 1 pixel == 1 byte */
default:
printk(KERN_ERR "cirrusfb: mode %dx%dx%d rejected..."
@@ -658,43 +649,29 @@
return -EINVAL;
}
- if (var->xres * nom / den * var->yres > info->screen_size) {
- printk(KERN_ERR "cirrusfb: mode %dx%dx%d rejected..."
- "resolution too high to fit into video memory!\n",
- var->xres, var->yres, var->bits_per_pixel);
- DPRINTK("EXIT - EINVAL error\n");
- return -EINVAL;
- }
-
+ if (var->xres_virtual < var->xres)
+ var->xres_virtual = var->xres;
/* use highest possible virtual resolution */
- if (var->xres_virtual == -1 &&
- var->yres_virtual == -1) {
- printk(KERN_INFO
- "cirrusfb: using maximum available virtual resolution\n");
- for (i = 0; modes[i].xres != -1; i++) {
- int size = modes[i].xres * nom / den * modes[i].yres;
- if (size < info->screen_size / 2)
- break;
- }
- if (modes[i].xres == -1) {
- printk(KERN_ERR "cirrusfb: could not find a virtual "
- "resolution that fits into video memory!!\n");
- DPRINTK("EXIT - EINVAL error\n");
- return -EINVAL;
- }
- var->xres_virtual = modes[i].xres;
- var->yres_virtual = modes[i].yres;
+ if (var->yres_virtual == -1) {
+ var->yres_virtual = pixels / var->xres_virtual;
printk(KERN_INFO "cirrusfb: virtual resolution set to "
"maximum of %dx%d\n", var->xres_virtual,
var->yres_virtual);
}
-
- if (var->xres_virtual < var->xres)
- var->xres_virtual = var->xres;
if (var->yres_virtual < var->yres)
var->yres_virtual = var->yres;
+ if (var->xres_virtual * var->yres_virtual > pixels) {
+ printk(KERN_ERR "cirrusfb: mode %dx%dx%d rejected... "
+ "virtual resolution too high to fit into video memory!\n",
+ var->xres_virtual, var->yres_virtual,
+ var->bits_per_pixel);
+ DPRINTK("EXIT - EINVAL error\n");
+ return -EINVAL;
+ }
+
+
if (var->xoffset < 0)
var->xoffset = 0;
if (var->yoffset < 0)