fbmem: Check virtual screen sizes in fb_set_var()

Verify that the fbdev or drm driver correctly adjusted the virtual
screen sizes. On failure report the failing driver and reject the screen
size change.

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # v5.4+
This commit is contained in:
Helge Deller 2022-06-29 15:53:55 +02:00
parent e64242caef
commit 6c11df58fd

View File

@ -1017,6 +1017,16 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
if (ret)
return ret;
/* verify that virtual resolution >= physical resolution */
if (var->xres_virtual < var->xres ||
var->yres_virtual < var->yres) {
pr_warn("WARNING: fbcon: Driver '%s' missed to adjust virtual screen size (%ux%u vs. %ux%u)\n",
info->fix.id,
var->xres_virtual, var->yres_virtual,
var->xres, var->yres);
return -EINVAL;
}
if ((var->activate & FB_ACTIVATE_MASK) != FB_ACTIVATE_NOW)
return 0;