RE: [PATCH v3] staging: fbtft: core: set smem_len before fb_deferred_io_init call

[Liu, Chuansheng]

Hi Peter,

> -----Original Message-----
> From: Peter Suti <peter.suti@xxxxxxxxxxxxxxxxxxx>
> Sent: Wednesday, July 27, 2022 3:36 PM
> To: Liu, Chuansheng <chuansheng.liu@xxxxxxxxx>; dan.carpenter@xxxxxxxxxx;
> Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; Thomas Zimmermann
> <tzimmermann@xxxxxxx>; Javier Martinez Canillas <javierm@xxxxxxxxxx>
> Cc: Peter Suti <peter.suti@xxxxxxxxxxxxxxxxxxx>; dri-
> devel@xxxxxxxxxxxxxxxxxxxxx; linux-fbdev@xxxxxxxxxxxxxxx; linux-
> staging@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH v3] staging: fbtft: core: set smem_len before
> fb_deferred_io_init call
> 
> The fbtft_framebuffer_alloc() calls fb_deferred_io_init() before
> initializing info->fix.smem_len.  It is set to zero by the
> framebuffer_alloc() function.  It will trigger a WARN_ON() at the
> start of fb_deferred_io_init() and the function will not do anything.

Please show us the WARN_ON() call stack, then everything is clear. It is the driver itself issue to be fixed.
I saw Thomas made such WARN_ON().

> 
> Fixes: 856082f021a2 ("fbdev: defio: fix the pagelist corruption")

Don't agree with such description.

Best Regards
Chuansheng