[PATCH v3 3/4] fbmem: Check virtual screen sizes in fb_set_var()

[Geert Uytterhoeven]

Hi Helge,

On Wed, Jul 6, 2022 at 5:02 PM Helge Deller <deller at gmx.de> wrote:
> 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 at gmx.de>

> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -1016,6 +1016,17 @@ 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 (%dx%d vs. %dx%d)\n",

%ux%u cs. %ux%u

Please don't split messages, for easier grepping.

> +                       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;

With the above fixed:
Reviewed-by: Geert Uytterhoeven <geert at linux-m68k.org>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds