Re: [PATCH 2/5] fbcon: Fix up user-provided virtual screen size
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2022-06-30 19:01:01
Also in:
dri-devel
Hi Helge, On Wed, Jun 29, 2022 at 10:00 PM Helge Deller [off-list ref] wrote:
The virtual screen size can't be smaller than the physical screen size. Based on the general rule that we round up user-provided input if neccessary, adjust the virtual screen size as well if needed. Signed-off-by: Helge Deller <deller@gmx.de> Cc: stable@vger.kernel.org # v5.4+
Thanks for your patch!
quoted hunk ↗ jump to hunk
--- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c@@ -1106,6 +1106,11 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd, return -EFAULT; console_lock(); lock_fb_info(info); + /* adjust virtual screen size if user missed it */ + if (var.xres_virtual < var.xres) + var.xres_virtual = var.xres; + if (var.yres_virtual < var.yres) + var.yres_virtual = var.yres; ret = fb_set_var(info, &var); if (!ret) fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL);
Given "[PATCH 4/5] fbmem: Prevent invalid virtual screen sizes in
fb_set_var", I don't think we need this patch. Moreover, this
patch will prevent triggering the WARN_ON()s in [PATCH 4/5] in the
most common buggy case of drivers plainly ignoring var.[xy]res_virtual.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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