From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mats Petersson Subject: Re: VGA passthrough and AMD drivers Date: Fri, 7 Dec 2012 17:04:31 +0000 Message-ID: <50C2219F.5050505@citrix.com> References: <36774CA35642C143BCDE93BA0C68DC5702C53A0A@dulac> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; Format="flowed" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <36774CA35642C143BCDE93BA0C68DC5702C53A0A@dulac> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 07/12/12 16:51, Aur=E9lien MILLIAT wrote: > > >> Hi all, > > >> > > >> I have made some tests to find a good driver for FirePro V8800 on > > >> windows 7 64bit HVM. > > >> > > >> I have been focused on ?advanced features?: quad buffer and active > > >> stereoscopy, synchronization ? > > >> > > >> The results, for all FirePro drivers (of this year); I can?t get the > > >> quad buffer/active stereoscopy feature. > > >> > > >> But they work on a native installation. > > >> > > >Can you describe the setup a little more? > > I=92ve got 2 HP Z800 workstation with FirePro V8800, one per computer. > > It=92s a setup used in CAVE system, I try (and its works, minus some = > issues) to virtualize =91virtual reality contexts=92 that needs full = > graphics card features. > > Intel Xeon E5640 CPU with Intel 5520 chipset > > cores_per_socket : 4 > > threads_per_core : 2 > > cpu_mhz : 2660 > > total_memory : 4079 > > >How many graphic cards per guest? > > One card per guest. > > >How many guests? On how many hosts? > > One guest per computer. > And of course, I just thought of some other questions: What version of Xen are you using? What kernel are you using in Dom0? And just to be clear, there is only Dom0 and one Windows 7 HVM guest on = each machine? > >> > > >> The only driver that allows this feature is a Radeon HD driver > > >> (Catalyst 12.10 WHQL). > > >> > > >> But this driver becomes unstable when an application using active > > >> stereo and synchronization is closed: > > >> > > >> -The synchronization between two computers is lost. > > >> > > >> -The CCC can crash when the synchronization is made again. > > >> > > >> Someone have any clues about this? > > >> > > >I don't know exactly how this works on AMD/ATI graphics cards, but I > > >have worked with synchronisation on other graphics cards about 7 years > > >ago, so I have some idea of how you solve the various problems. > > > > > >What I don't quite understand is why it would be different between a > > >virtual environment and the bare-metal ("native") install. My immediate > > >guess is that there is a timing difference, for one of two reasons: > > >1. IOMMU is adding extra delays to the graphics card reading system memo= ry. > > >2. Interrupt delays due to hypervisor. > > >3. Dom0 or other guest domains "stealing" CPU from the guest. > > >I don't think those are easy to work around (as they all have to > > >"happen" in a virtual system), but I also don't REALLY understand why > > >this should cause problems in the first place, as there isn't any > > >guarantee as to the timings of either memory reads, interrupt > > >latency/responsiveness or CPU availability in Windows, so the same > > >problem would appear in native systems as well, given "the right" > > >circumstances. > > > > > > > > >What exactly is the crash in CCC? > > > > > >(CCC stands for "Catalyst Control Center" - which I think is a Windows > > >"service" to handle certain requests from the driver that can't be done > > >in kernel mode [or shouldn't be done in the driver in general]). > > After the application is closed, I launch the Catalyst Control Center, = > the synchronization state seems to be good. But there is no = > synchronization. > > If I try to apply any modifications of synchronization (synchro server = > or client), CCC freeze and I need to kill it manually. > > I can set the synchronization back after this. > This clearly sounds like a software issue in the CCC itself. I could be = wrong, but that's what I think right now. It would be rather difficult = to figure out what is going wrong without at least a repro environment. Whilst I'm all for using Xen for everything, there are sometimes = situations when "not using Xen" may actually be the right choice. Can = you explain why running your guests in Xen is of benefit? [If you'd like = to answer "none of your business", that's fine, but it may help to = understand what the "business case" is for this]. -- Mats > > I will try next week with others computers. > > Thanks for the reply, > > Aurelien > > -- > > Mats > > > > > > Thanks, > > > > > > Aurelien > > > >