How to enable Radeon Pro Duo with mesa

[Christian König]

Am 15.03.2018 um 08:09 schrieb Lvzhihong (ReJohn):
>> What are you trying to do?  A large desktop spread across both chips?
>> Use the chips independently?  There is no support for crossfire on Linux.  If you want to use a desktop across multiple chips or select which chip is used for rendering, you can use xrandr and the prime support in X:
>> https://wiki.archlinux.org/index.php/PRIME
> I want to select one chip to render for my application. And now I know how to select which chip: after set env DRI_PRIME=1 , the second chip will be used. But there is another problem: the second chip's performance is very bad , only 1/4 of the first chip.
>
> xrandr --listproviders:
> Providers: number : 2
> Provider 0: id: 0x7f cap: 0x9, Source Output, Sink Offload crtcs: 6 outputs: 4 associated providers: 1 name:AMD Radeon (TM) Pro WX 7100 Graphics @ pci:000d:33:00.0 Provider 1: id: 0x45 cap: 0x6, Sink Output, Source Offload crtcs: 6 outputs: 0 associated providers: 1 name:AMD Radeon (TM) Pro WX 7100 Graphics @ pci:000d:34:00.0
>
> Here is the results of running glxgears:
> DRI_PRIME=1 vblank_mode=0  glxgears
> ATTENTION: default value of option vblank_mode overridden by environment.
> 5486 frames in 5.0 seconds = 1097.200 FPS
>
> DRI_PRIME=0 vblank_mode=0  glxgears
> ATTENTION: default value of option vblank_mode overridden by environment.
> 19846 frames in 5.0 seconds = 3969.058 FPS
>
> How to resolve this?

This is expected. glxgears is not a real GPU benchmark, but rather a CPU 
benchmark of how fast we can page flip when vblank is disabled.

Since doing the rendering on one GPU and presenting it on another GPU is 
more work this will result in much lower fps.

Try something real and compare the numbers.

Regards,
Christian.

>
>
>> On Wed, Mar 14, 2018 at 5:41 AM, Lvzhihong (ReJohn) <lvzhihong1 at huawei.com> wrote:
>> Hi All ,
>>
>> Does mesa support Radeon Pro Duo? I don’t know how to configure
>> xorg.conf to use two WX7100 card of DUO , and now I can only use the first card of DUO.
>>
>> What are you trying to do?  A large desktop spread across both chips?
>> Use the chips independently?  There is no support for crossfire on Linux.  If you want to use a desktop across multiple chips or select which chip is used for rendering, you can use xrandr and the prime support in X:
>> https://wiki.archlinux.org/index.php/PRIME
>>
>> Alex
>
>> Installed software packages: xserver-xorg  xfce4  xinit
>>
>> Mesa version: 17.2.8  kernel version: 4.15
>>
>>
>>
>> Pci information:
>>
>> 000d:31:00.0 PCI bridge: PLX Technology, Inc. PEX 8747 48-Lane, 5-Port
>> PCI Express Gen 3 (8.0 GT/s) Switch (rev ca)
>>
>> 000d:32:08.0 PCI bridge: PLX Technology, Inc. PEX 8747 48-Lane, 5-Port
>> PCI Express Gen 3 (8.0 GT/s) Switch (rev ca)
>>
>> 000d:32:10.0 PCI bridge: PLX Technology, Inc. PEX 8747 48-Lane, 5-Port
>> PCI Express Gen 3 (8.0 GT/s) Switch (rev ca)
>>
>> 000d:33:00.0 VGA compatible controller: Advanced Micro Devices, Inc.
>> [AMD/ATI] Ellesmere [Radeon Pro WX 7100]
>>
>> 000d:33:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI]
>> Device
>> aaf0
>>
>> 000d:34:00.0 Display controller: Advanced Micro Devices, Inc.
>> [AMD/ATI] Ellesmere [Radeon Pro WX 7100]
>>
>>
>>
>> My xorg.conf:
>>
>> Section "Device"
>>
>>         Identifier "AMD"
>>
>>         Driver "amdgpu"
>>
>>         BusID "pci:51 at 13:00:00"
>>
>> EndSection
>>
>> Section "Monitor"
>>
>>          Identifier "monitor0"
>>
>>          Option "enable" "true"
>>
>> EndSection
>>
>> Section "Screen"
>>
>>          Identifier "screen0"
>>
>>          Device "AMD"
>>
>>          Monitor "monitor0"
>>
>>          DefaultDepth 24
>>
>>          SubSection "Display"
>>
>>                  Depth 24
>>
>>          EndSubSection
>>
>> EndSection
>>
>>
>>
>> I use “startx” to start desktop , and only the first WX7100(PCI Bus ID:
>> 000d:33:00.0) being used , the second WX7100(PCI Bus ID: 000d:34:00.0)
>> has no load .
>>
>>           Even if I set BusID as "pci:52 at 13:00:00" (the second WX7100),
>> it still only the first WX7100 being used.
>>
>>
>>
>>        So , How to enable Radeon Pro Duo with opensource driver , does
>> my xorg.conf is wrong or mesa doesn’t support Radeon Pro Duo?
>>
>>
>>
>>
>>
>>
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>> amd-gfx at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>>
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