4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Helge Deller <deller@xxxxxx>
commit 6c11df58fd1ac0aefcb3b227f72769272b939e56 upstream.
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@xxxxxx>
Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v5.4+
Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/video/fbdev/core/fbmem.c | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1006,6 +1006,17 @@ fb_set_var(struct fb_info *info, struct
if (ret)
goto done;
+ /* 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);
+ ret = -EINVAL;
+ goto done;
+ }
+
if ((var->activate & FB_ACTIVATE_MASK) == FB_ACTIVATE_NOW) {
struct fb_var_screeninfo old_var;
struct fb_videomode mode;
