Re: [PATCH v2 08/43] drm/fbdev: Add fbdev-shmem

Javier Martinez Canillas
2024-04-16T12:23:06Z

Thomas Zimmermann <tzimmermann@suse.de> writes:

[...]

>>
>> I guess is OK because is_vmalloc_addr() is always true for this case ?
>
> It's not a vmalloc'ed address, but see patch 7. Fbdev-shmem uses a new
> get_page callback in fb_defio. It provides the necessary page directly
> to fb_defio.
>

Thanks! That was the missing piece of the puzzle. I didn't look at that
patch because I noticed that already had a r-b. It makes more sense now :)

>
>>
>> This also made me think why info->fix.smem_len is really needed. Can't we
>> make the fbdev core to only look at that if info->screen_size is not set ?
>
> The fbdev core doesn't use smem_len AFAICT. But smem_len is part of the
> fbdev UAPI, so I set it. I assume that programs use it to go to the end
> of the framebuffer memory.
>

I see. Makes sense.

> Best regards
> Thomas
>

--
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat