Re: [Xen-users] Xen 4.7.0 graphics pass through problems (Win10, AMD Radeon)

[Peter Milesson <miles@xxxxxxxx>]

Hi again,

I've been playing around a bit more.

It seems one of the problems is that I passed a couple of PCI-devices 
(USB controllers) to the VM, beside the graphics card.
When I pass the USB-devices individually in the VM configuration file 
(usbdevice=['tablet','host:1.4','host:1:9','host:x.y']), the display 
problems seem to be more or less gone.
IMHO, if you work in a VM with graphics, keyboard, mouse, etc., it's 
much simpler just pass the PCI-devices for a USB port, and you can 
connect whatever USB hubs and devices. With the method above, one has 
got to list the devices specifically. And I connect and disconnect a 
bunch of different USB-devices (barcode readers, docking stations, 
1-wire devices, serial ports, etc.) frequently.
I'm going to play around with this a little more, and publish my 
findings here. If somebody has got any idea how to allocate a whole 
USB-port, without passing a PCI-device, I would be happy to know.
Best regards,

Peter

On 2016-09-09 09:51, Peter Milesson wrote:
> Hi folks,
>
> I've been using Xen for 3 years, starting out with 4.2, and I've been 
> upgrading regularly, and installed 4.7.0 today.
> I'm using Windows 10, 64-bit with PCI pass through in a VM with 
> PV-drivers, using a AMD Radeon HD6450 card (AMD graphics cards don't 
> seem to need graphics pass through)
> Previously (up till Xen 4.6.3), the graphics output has displayed some 
> shorter lines, a bit like thin coarse snow, when watching videos. The 
> distortions stayed within the movie, and was tolerable.
> After upgrade to Xen 4.7.0, the video performance is seriously ugly. 
> Just for example, I open cnn.com and move the mouse pointer up and 
> down over the photos, which creates a bunch of flickering lines over 
> the display. The same with moving content in Youtube for example. Or 
> opening a Cygwin terminal window and scrolling through a file. Terrible.
> Nothing else has changed, only the Xen version.
>
> The current situation is far from acceptable, and my question is, if 
> somebody else has got the same experiences, and possibly if there's a 
> solution.
> If somebody has got a solution here, I'd be very grateful.
>
> Hardware and OS details below.
>
> Best regards,
>
> Peter
>
> *Hardware*
> CPU: AMD FX-6100 (6-core)
> Chipset: AMD 970A (has got a working IOMMU)
> RAM: 16GB DDR3-1600MHz
> Video: AMD Radeon HD6450
>
> *OS*
> Linux Slackware 14.2 (latest)
> Kernel: 4.4.19 long term stable
>
> *Xen*
> Version: 4.7.0 (configure same as 4.6.3 and previous versions)
>  ./configure --prefix=/usr --localstatedir=/var --sysconfdir=/etc 
> --libdir=/usr/lib64 --with-xenstored=oxenstored 
> --disable-qemu-traditional --disable-rombios --disable-stubdom
> Xen dom0 boot entry (grub2):
> menuentry "Xen 4.7.0 / Slackware 14.2 (kernel 4.4.19-dom0)" {
>        set root=(hd0,1)
>        multiboot /boot/xen-4.7.0.gz iommu=1 dom0_mem=2048M 
> dom0_max_vcpus=2 dom0_vcpus_pin console=vga cpufreq=xen:performance 
> noreboot
>        module /boot/vmlinuz-4.4.19-dom0 console=vga earlyprintk=xen 
> root=/dev/sda1 ro clocksource=xen xencons=off
> }
>
> *Guest OS*
> Windows 10 Pro 64-bit (2VCPUs)
> Latest PV Drivers (8.2 series)
> Graphics driver: Latest WHQL driver 15.201.1151.1008
>
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxx
> https://lists.xen.org/xen-users

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