[PATCH] fbdev: Pan display fixes
- Fix fb_pan_display rejecting yoffsets that are valid if panning mode
is ywrap.
- Add more robust error checking in fb_pan_display specially since this
function is accessible by userland apps.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index 6240aed..10dfdf0 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -722,14 +722,30 @@
int
fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
{
+ struct fb_fix_screeninfo *fix = &info->fix;
int xoffset = var->xoffset;
int yoffset = var->yoffset;
- int err;
+ int err = 0, yres = info->var.yres;
- if (xoffset < 0 || yoffset < 0 || !info->fbops->fb_pan_display ||
- xoffset + info->var.xres > info->var.xres_virtual ||
- yoffset + info->var.yres > info->var.yres_virtual)
- return -EINVAL;
+ if (var->yoffset > 0) {
+ if (var->vmode & FB_VMODE_YWRAP) {
+ if (!fix->ywrapstep || (var->yoffset % fix->ywrapstep))
+ err = -EINVAL;
+ else
+ yres = 0;
+ } else if (!fix->ypanstep || (var->yoffset % fix->ypanstep))
+ err = -EINVAL;
+ }
+
+ if (var->xoffset > 0 && (!fix->xpanstep ||
+ (var->xoffset % fix->xpanstep)))
+ err = -EINVAL;
+
+ if (err || !info->fbops->fb_pan_display || xoffset < 0 ||
+ yoffset < 0 || var->yoffset + yres > info->var.yres_virtual ||
+ var->xoffset + info->var.xres > info->var.xres_virtual)
+ return -EINVAL;
+
if ((err = info->fbops->fb_pan_display(var, info)))
return err;
info->var.xoffset = var->xoffset;