Re: [PATCH v2 05/19] fbdev/sysfs: Fix locking

Thomas Zimmermann
2022-02-10T11:22:08Z

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Am 08.02.22 um 22:08 schrieb Daniel Vetter:
> fb_set_var requires we hold the fb_info lock. Or at least this now
> matches what the ioctl does ...
>
> Note that ps3fb and sh_mobile_lcdcfb are busted in different ways here,
> but I will not fix them up.
>
> Also in practice this isn't a big deal, because really variable fbdev
> state is actually protected by console_lock (because fbcon just
> doesn't bother with lock_fb_info() at all), and lock_fb_info
> protecting anything is really just a neat lie. But that's a much
> bigger fish to fry.
>
> Acked-by: Sam Ravnborg <sam@ravnborg.org>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Helge Deller <deller@gmx.de>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Qing Wang <wangqing@vivo.com>
> Cc: Sam Ravnborg <sam@ravnborg.org>

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>

> ---
> drivers/video/fbdev/core/fbsysfs.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c
> index 26892940c213..8c1ee9ecec3d 100644
> --- a/drivers/video/fbdev/core/fbsysfs.c
> +++ b/drivers/video/fbdev/core/fbsysfs.c
> @@ -91,9 +91,11 @@ static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var)
>
> var->activate |= FB_ACTIVATE_FORCE;
> console_lock();
> + lock_fb_info(fb_info);
> err = fb_set_var(fb_info, var);
> if (!err)
> fbcon_update_vcs(fb_info, var->activate & FB_ACTIVATE_ALL);
> + unlock_fb_info(fb_info);
> console_unlock();
> if (err)
> return err;

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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