Multiple video cards

[Warren Block]

On Tue, 29 Jul 2014, Zane C. B-H. wrote:

> On Sun, 27 Jul 2014 17:17:43 -0600 (MDT)
> Warren Block <wblock at wonkity.com> wrote:
>
>> Test system:
>>
>> FreeBSD 10-STABLE amd64 r269160
>> AMD A8-3850 APU (Radeon HD6550D)
>> Radeon X1650 PCIe card
>>
>> Under IGX Configuration, the APU motherboard BIOS has a "Surround
>> View" setting.  When enabled, the onboard HD6550 GPU remains
>> enabled when an additional video card is connected.
>>
>> With the HD6550 disabled, the X1650 works fine.  pciconf shows only
>> one video device.
>>
>> With the HD6550 enabled, both video devices show in pciconf, and X
>> gives the "screens not found" error unless both are defined in
>> xorg.conf.  X starts, but xrandr only shows the HD6550, and only
>> the monitors attached to the motherboard video connectors work.
>> xrandr only shows that cards.
>>
>> There may be more settings required in xorg.conf.  I think that
>> Xinerama is obsolete, but don't know.
>>
>> Based on some Linux stuff:
>> % xrandr --listproviders
>> RandR 1.4 not supported
>>
>> Is there a right way to define multiple monitors on more than one
>> card for the same virtual screen?
>
> You are most likely looking at using Xinerama there, unless the
> Radeon driver has something specific for it like Nvidia driver does.
> The man page should give you a better idea of what exactly you need
> to do.

Well, yes, except Xinerama is, I think, obsolete.  It's was what we used 
back in the old days of single-output video boards.  There should be a 
new xrandr way to do this.  Whether that code is part of the version of 
xorg currently available in FreeBSD, I don't know.

> As to configuring it, enable them both and do "X -configure" to build
> it. That should autodect all cards and shove them into a config.

Well, there is some conflict.  After deleting xorg.conf.new and 
re-running Xorg -configure:

   (++) Using config file: "/root/xorg.conf.new"
   (II) [KMS] No DRICreatePCIBusID symbol, no kernel modesetting.
   (II) [KMS] No DRICreatePCIBusID symbol, no kernel modesetting.
   Segmentation fault at address 0x0

   Fatal server error:
   Caught signal 11 (Segmentation fault). Server aborting

So it manages to create xorg.conf.new, but then croaks.  Given the 
repeat of that error, I'm guessing it fails once for each card.

An attempt to use that xorg.conf.new gives the same results: only the 
monitor attached to the HD6550 comes on.

> You will likely need to learn to do some tweaking as it rarely 
> properly detects the proper driver to use, meaning it will default to 
> "vesa".

The vesa driver is used in the generated xorg.conf.new, but I think the 
conflict is between two instances of the radeon driver.  I might try it 
with a single Radeon in a system with Intel video.