[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-users] VGA/PCI Passthrough of Secondary Graphics Adapter

1) If passing declaring the BDF is all that is needed to pass a VGA card, in the same respect as an PCI device, then there is no difference between PCI passthrough and VGA passthrough IF the VGA card being passed through is not in use by the dom0?

2) The card I wish to pass is the 5570, in the secondary PCIe slot. It is not being used by the dom0, and is subsequently hidden (xen-pciback.hide).

3) Neither Radeon in my system supports FLR; however, many people use the Radeon with VGA passthrough somewhat routinely.  I seem to be having immense trouble getting this to work?  I have not gotten anything to display other than a black screen (which does show that something is happening).  I just can't understand why?

And regarding the BSODs, when I install the card, I've gotten it to say "Functioning normally" in Device Manager, but the screen is disabled in "Screen Resolution," and the when I attempt to "Extend to Display" in order to enable the Radeon monitor, the screen goes blank and the system crashes.  Upon reboot, the system BSODs (atikmpag.sys)  I've tried physically powering down dom0 and bringing it back up, but the error persists. 

As an aside, I've compiled Xen with a patch that supposedly fixes these issues (patches qemu-dm), and I've attempted to use the script provided (run-passthrough), but that hasn't resulted in any change whatsoever.

I greatly appreciate your time in assisting me!

On Sat, Apr 27, 2013 at 3:30 PM, Casey DeLorme <cdelorme@xxxxxxxxx> wrote:
Hello Alex,

To answer your first question, simply provide the BDF (Bus Device Function) from lspci.

My understanding is that graphics devices are missing a translation for legacy processes, such as boot code, and this varies by device.

I am using the onboard graphics with Dom0 as the primary, and passing a Radeon HD 6870 to a virtual machine.  Graphics cards are not "shared", so even if it was your primary card you would have to remove it from Dom0 to pass it.

The BSoD you are encountering, does it happen when you reboot?  In my experience this is caused by the lack of FLR (Function Level Reset) in consumer cards, the solution is manual ejection and if you install drivers without being aware of the problem it will still experience odd problems.

Experience varies however, my advice would be to check the marksmail search engine for Function Level Reset or Passthrough BSOD.


On Sat, Apr 27, 2013 at 7:16 PM, Alex Karaoui <code3studios@xxxxxxxxx> wrote:

Concisely, I've been trying for several days to get VGA/PCI passthrough
working.  Regarding VGA vs PCI passthrough, I'm not entirely certain of the
difference?  Does Xen perform a different set of operations when passing
through a VGA card versus any PCIe card?  I've read the wiki and it seems
the answer is "yes;" however, when passing through a graphics adapter, how
would I instruct Xen/qemu-dm that said adapter is a graphics card and not a
normal PCIe card?

In essence, how does one pass-through a graphics card that is NOT the
primary adapter (my BIOS does not boot with it)?

My problem is somewhat complex.  I have two Radeon cards (one 5870 as
primary, and one 5570 as secondary).  The BIOS boots with the 5870 and I
cannot swap the cards due to space constraints within the case.  Linux then
boots using the 5870.  I've hidden the 5570 using pciback (compiled in the
kernel not as a module).  I can successfully get a Windows 7 32-bit domU to
see the card, and install the drivers.

However on boot, the system BSODs due to an Error 116 in atikmpag.sys!  I
can avoid this if I use an older driver (10.x series), without Catalyst
Control Center.  However, even using the older driver, or the Microsoft
driver, neither results in actual display from the graphics card.  I get
nothing.  The most I've gotten is a black screen, and then the system will

I've searched the mailing lists, and I've done every permutation of
configurations I can think of.  I'm stumped!  I'm left with the belief that
I cannot pass-through the secondary graphics adapter.  I need to, because I
don't have a second computer at the moment, and I need the primary adapter
to operate dom0.  I've thought of running Linux off the secondary adapter,
but it doesn't seem possible with the open-source radeon driver and fglrix
(closed-source) won't work with Xen apparently.

Am I missing something, here?  Any help would be appreciated!

View this message in context: http://xen.1045712.n5.nabble.com/VGA-PCI-Passthrough-of-Secondary-Graphics-Adapter-tp5715723.html
Sent from the Xen - User mailing list archive at Nabble.com.

Xen-users mailing list

Xen-users mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.