[pvrusb2] Qemu and usb

[Xavier Gnata]

Bjorn Danielsson wrote:
> 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?
>
>   
I think it is a well known pb with qemu/kvm but you should ask on the 
kvm devel list (or qemu).
If you do so on the qemu one, please cc me because I'm only on the 
kvm-devel list :)

Xavier