[pvrusb2] Qemu and usb

[Bjorn Danielsson]

Xavier Gnata <xavier.gnata at gmail.com> wrote:
>[...]
> Well I have learned that qemu (or kvm) has no usb2 support. Only usb1 
> (no way plug my ipod under kvm).
>
> One great chanlenge to get usb2 support in qemu is to find a way to 
> implement EHCI without having to rely on very accurate timers.
> IMHO, it is why you can see missing frames.

Yes, dmesg on the qemu guest reported uhci only, no ehci.

But the pvrusb2 device itself works perfectly well with a usb1.1
host as long as you stick with the default configuration, which
is 6 Mbit/s for my PAL device. I used an xbox as the host computer
for several years, and the xbox only has usb1.1. It worked flawlessly
without ehci...

There are indications of timing problems in the dmesg log of the
guest OS (which was an old 32-bit slackware 12.0 image), but I
haven't yet been able to figure out what those messages mean.

Pasting a portion of dmesg from the qemu guest:

usb 1-2: new full speed USB device using uhci_hcd and address 2
Clocksource tsc unstable (delta = 484081886 ns)
Time: pit clocksource has been installed.
usb 1-2: configuration #1 chosen from 1 choice
i2c_core: exports duplicate symbol i2c_smbus_write_i2c_block_data (owned by kernel)
Linux video capture interface: v2.00
usbcore: registered new interface driver pvrusb2
drivers/media/video/pvrusb2/pvrusb2-main.c: Hauppauge WinTV-PVR-USB2 MPEG2 Encoder/Tuner : V4L in-tree version

Where does that "Clocksource tsc unstable" stuff come from?

-- 
Bjorn Danielsson  <pvr-usb2 at dax.nu>