[REGRESSION]: drivers/firmware: move x86 Generic System Framebuffers support

[Javier Martinez Canillas]

Hello Ilya,

On 11/11/21 01:45, Ilya Trukhanov wrote:

[snip]

>> Can you please share the kernel boot log for any of these cases too ?
>

Thanks a lot for the testing and providing the info!
 
>> This is just a guess though. Would be good if you could test following cases:
>>
>> 1) CONFIG_FB_EFI not set
> 
> /proc/fb:
> 0 amdgpu
> 
> dmesg: https://pastebin.com/c1BcWLEh
> 
> Suspend-to-RAM works.
> 
>> 2) CONFIG_FB_EFI=y and CONFIG_DRM_AMDGPU=m
> 
> /proc/fb before `modprobe amdgpu`:
> 0 EFI VGA
> 
> after:
> 0 amdgpu
> 
> dmesg: https://pastebin.com/vSsTw2Km
> 
> Suspend-to-RAM works.
> 
>> 3) CONFIG_SYSFB_SIMPLEFB=y and CONFIG_FB_SIMPLE=y
> 
> /proc/fb:
> 0 amdgpu
> 1 simple
> 
> dmesg: https://pastebin.com/ZSXnpLqQ
> 
> Suspend-to-RAM fails.
> 
>>
>> And for each check /proc/fb, the kernel boot log, and if Suspend-to-RAM works.
>>
>> If the explanation above is correct, then I would expect (1) and (2) to work and
>> (3) to also fail.
>>

Your testing confirms my assumptions. I'll check how this could be solved to
prevent the efifb driver to be probed if there's already a framebuffer device.

Best regards,
-- 
Javier Martinez Canillas
Linux Engineering
Red Hat