GPU selection

[Pete Wright]

On 9/22/20 1:11 AM, Grzegorz Junka wrote:
>
> On 21/09/2020 17:14, Pete Wright wrote:
>>
>>
>> On 9/21/20 12:09 AM, Grzegorz Junka wrote:
>>> On 21/09/2020 00:45, Jan Beich wrote:
>>>> Grzegorz Junka <list1 at gjunka.com> writes:
>>>>
>>>>> With the new drm-kmod, is it possible to specify which card should be
>>>>> used for X11?
>>>> Do you mean BusID in xorg.conf(5) ?
>>>
>>> That's the reason why I am asking, in the new X11 there is no 
>>> xorg.conf file. At least I don't seem to be able to find one. It's 
>>> all configured automatically through mode setting if I understand 
>>> this correctly?
>>
>> You can still use an xorg.conf with xorg-1.20.x, but the recommend 
>> method is to let auto-detection work.  what i do is drop 
>> configuration snippets in /usr/local/etc/x11/xorg.conf.d/. for 
>> example when testing out adjustments to my GPU I have a file 
>> 10-amdgpu.conf which includes the pertinent configuration section for 
>> that device - for example:
>>
>> Section "Device"
>>     Identifier  "Card0"
>>     Driver      "amdgpu"
>>     BusID       "PCI:38:0:0"
>> EndSection
>>
>> hope this is helpful,
>> -pete
>>
> Yes, this helps. Thanks. If I understand this correctly, this would be 
> needed if I wanted to use both cards, otherwise I can just install 
> either NVidia or AMD driver and they would pick up the right hardware 
> as the default one to use with xorg automatically?
>

that is what I would expect to happen, so it may be worth experimenting 
with that.  although, i wouldn't be surprised if you would need to 
specify an Xorg config to ensure your desired video card is used.

one thing that is helpful that I forgot to mention - Xorg driver 
packages (xf86-video-amdgpu for example) drop an example code snippet in 
/usr/local/share/X11/xorg.conf.d/ suitable for use in 
/usr/local/etc/X11/xorg.conf.d/.  this has helped me when setting things 
up since i don't have to start from scratch.

-p

-- 
Pete Wright
pete at nomadlogic.org
@nomadlogicLA