Re: [Xen-users] ATI VGA Passthrough / Xen 4.2 / Linux 3.8.6

[Peter Maloney <peter.maloney@xxxxxxxxxxxxxxxxxxxx>]

On 2013-04-15 10:32, Aurélien MILLIAT wrote:
>> De : xen-users-bounces@xxxxxxxxxxxxx 
>> [mailto:xen-users-bounces@xxxxxxxxxxxxx] De la part de Gordan Bobic
>> Envoyé : lundi 15 avril 2013 00:47
>> À : xen-users@xxxxxxxxxxxxx
>> Objet : [Xen-users] ATI VGA Passthrough / Xen 4.2 / Linux 3.8.6
>>
>> Hi,
>>
>> I'm trying to get VGA passthrough to work to an XP x64 guest, and I'm seeing 
>> "interesting" things happening.
>>
>> I'm using the kernel and userspace tools from here:
>> http://xen.crc.id.au/support/guides/install/#
>> on Scientific Linux 6.
>>
>> I gave up on trying to get an Nvidia card to work in the guest having read 
>> about the extra patches required to get a non-Quadro card to work. 
>> So I switched to using an ATI 6450/7450 card. This works fine - almost. 
>> ATI cards have a secondary audio output device function on them for 
>> outputting audio over HDMI outputs. When I pass both the VGA and >the HDMI 
>> audio devices from the host to the guest, the guest cannot use the VGA card. 
>> It always shows up as unusable in the guest (yellow >exclamation mark in XP 
>> x64).
I had this problem (windows XP only), and fixed it by setting:

stdvga=1

Which means something like: replace the cirrus logic emulated card with
a stdvga emulated card.

And then I guess what happens is: winxp is too old to understand the new
card ;) and has to fall back to the passed through one, and somehow that
makes it work, maybe because it initializes it differently during boot
up (when starting the AMD graphics driver).

Also, make sure you have already installed the AMD graphics drivers in XP.

And be sure you set gfx_passthrough=0 (secondary passthrough, with AMD
support) rather than =1 (primary passthrough, without AMD support)

>>
> I've got the same behavior with Quadro FX3800. One possible workaround for 
> that is to deactivate then to activate the card in your domU and reboot it.
> Check if you have FLR function (lspci -vv): 
> http://wiki.xen.org/wiki/Xen_PCI_Passthrough#How_can_I_check_if_PCI_device_supports_FLR_.28Function_Level_Reset.29_.3F
> I think this behavior is linked to the non-support of this function.
The patches AMD sent the xen devs, plus the passthrough support in the
driver, are supposed to handle this lack of FLR.
>
> Aurelien
>
>> What is the best way to debug this further?
>>
>> Gordan


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users