From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gordan Bobic Subject: Re: Windows 8 VGA Passthrough Date: Sun, 27 Oct 2013 19:35:45 +0000 Message-ID: <526D6B11.5080803@bobich.net> References: <526C2D06.1030606@gmail.com> <526CDD22.6080107@bobich.net> <526D22D9.6010006@gmail.com> <526D3D91.5090906@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <526D3D91.5090906@gmail.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: John Wargo , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On 10/27/2013 04:21 PM, John Wargo wrote: > On 10/27/2013 09:27 AM, John Wargo wrote: >> On 10/27/2013 04:30 AM, Gordan Bobic wrote: >>> On 10/26/2013 09:58 PM, John Wargo wrote: >>>> Geniuses, >>>> >>>> I've been trying to get VGA pass-through working on Windows 8, however >>>> I've been running into a few issues. >>>> Currently I can get Windows 8 running flawlessly without VGA >>>> pass-through, however I'm planning on using it for gaming, so this wont >>>> work. >>>> >>>> When I start windows 8, I am able to get past the install portion of >>>> the >>>> DVD, however it hangs on "Getting devices ready.. (n%)". >>>> >>>> Hardware Information : >>>> AMD Fx6300 >>>> ASUS M5a99x evo r2.0 >>>> 16GB RAM >>>> 6670 Radeon HD - Dom0 >>>> 7850 Radeon HD - Win8 >>> >>> I have recently (recently as in over the past 48 hours) re-tried to >>> get ATI VGA passthrough working, and the results are... interesting. >>> >>> HD4850 dom0 + HD7450 domU worked fine - or as fine as ATI passthrough >>> ever seems to work (slowdown + white lines when dragging windows >>> after a domU reboot). I am using XP64 domU so I can't eject the GPU >>> (it says it is being used). But shutting down the domU, doing echo 1 >>> > reset for the GPU from dom0 (I don't know how this is implemented >>> and whether it does anything) and then starting it up again sometimes >>> recovers it. GPU-Z runs and reports the GPU correctly. >>> >>> HD4850 dom0 + HD7970 domU results in the entire host locking up as >>> soon as the driver is loaded in domU. My solution is to swap the dom0 >>> GPU for an 8800GT, and the problem now doesn't occur. If I had to >>> guess, BIOS on the HD7970 does something bizzare, finds the HD4850 on >>> the bus, tries to do something to it, and ends up crashing the host. >>> This could also be exacerbated by the fact that I have to run with >>> relaxed checking and no PCI ACS due to NF200 bridges on my >>> motherboard. Even so, however, GPU-Z crashes the domU and it's GPU >>> _hard_ (but not the host, thankfully). It crashes it so hard, that >>> the only cure is to reboot the host. Reseting the GPU via /sys/ >>> doesn't seem to do anything to help. >>> >>> Are you using gfx_passthru=1 in your config? The way most people have >>> this kind of thing working is with gfx_passthru=0, i.e. secondary >>> passthru. Don't assign the PCI device in the config when installing. >>> Once the domU install is complete, shut it down, and add the GPU you >>> want to pass through. Then fire up domU in VNC, install the driver, >>> and with a bit of luck it will come up with output on the external >>> monitor. >>> >>> Also make sure that radeon or radeonfb kernel drivers DO NOT load >>> before the device is assigned to xen-pciback. The exact way to ensure >>> this will depend on what distro and dom0 kernel you are using. >>> >>> Gordan >> Status update: >> >> The catalyst drivers appear to be working perfectly fine, device >> manager shows no errors, and everything works great, except that when >> I plug my monitor into the second card, I get "No Signal" on the >> monitor, then it shuts off. >> >> I though that secondary passthrough meant that it would pass the >> virtual adapter in as primary, but I could use my GPU that I passed >> through, so where am I wrong, and how do I do that? >> >> -John > I've been doing some research into my VGA passthrough, so I've gone > through the various debugging steps, and the only thing that I've found > out of place is with "xl dmesg" (attached). > > Where do I go from here? Sounds like your IOMMU may be buggy. You may need to set permissive=1 on your xen-pciback module. I cannot remember if xl uses the same configuration, but for xm you could try putting this in your /etc/xen/xend-config.sxp: (pci-passthrough-strict-check no) (pci-dev-assign-strict-check no) Gordan