BlackMagic USB3 video capture returns only blank frames in Windows (xHCI issue)

[Steinar H. Gunderson]

Hi,

I've got an Intensity Shuttle USB3; it's a HDMI video capture card. It doesn't have any Linux drivers, so I'm trying to get it to work in a Windows 10 guest inside QEMU. I'm running latest git as of today (2015-08-20). I use this command line:

sudo x86_64-softmmu/qemu-system-x86_64 -enable-kvm -smp 2 -m 4096 -acpitable file=/sys/firmware/acpi/tables/MSDM -drive file=/home/sesse/windows.raw,if=virtio,format=raw -cpu host -netdev tap,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0 -monitor stdio -device nec-usb-xhci,id=xhci -device usb-host,bus=xhci.0,vendorid=0x1edb,productid=0xbd3b -usbdevice tablet

(I will add that the seemingly logical “host:1edb:bd3b,bus=xhci.0” did _not_ add the device at all. I don't know why, probably some parser issue?)

The card is properly detected, and the driver thinks everything is fine, running on the virtualized USB3 host and all. Looking at usbmon, there's lots of isochronous frames during capture, and they reach the host (looking at USBpcap on the Windows 10 side). However, the driver refuses to capture any video—all frames become black in all applications I try (well, Media Express seems to hardly store any frames at all in the .avi). However, audio is captured without a hitch. Curiously enough, no dropped frames are reported. There's no sign of CPU shortage; both host and guest seem to be happy around 20% of one core.

I am fairly certain this is an issue with the xHCI driver in QEMU, because if I give it the entire USB controller via VT-d, it works flawlessly, with video and all. For reference, here's the associated command line I use for that (after I've unbound it from the Linux system):

sudo x86_64-softmmu/qemu-system-x86_64 -enable-kvm -smp 2 -m 4096 -acpitable file=/sys/firmware/acpi/tables/MSDM -drive file=/home/sesse/windows.raw,if=virtio,format=raw -cpu host -netdev tap,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0 -monitor stdio -usbdevice tablet -device pci-assign,host=00:14.0

I can get USB pcap logs from both sides if you want, but they are huge (gigabytes) since the data rate is so high.

[Thomas Huth (th-huth)]

Triaging old bug tickets... can you still reproduce this issue with the latest version of QEMU? Or could we close this ticket nowadays?

[Steinar H. Gunderson (sesse)]

I haven't tried this in a long time, and I already managed to do what I wanted to do (which was to write a free Linux driver :-) ). I guess you can close this; not because I believe it's fixed, but because it's not that important to me anymore.

[Thomas Huth (th-huth)]

OK, thanks for your reply ... so I'm closing this ticket now