[pvrusb2] Qemu and usb

[Xavier Gnata]

Bjorn Danielsson wrote:
> Mike Isely <isely at isely.net> wrote:
>   
>> On Sat, 18 Oct 2008, Bjorn Danielsson wrote:
>> [...]
>>     
>>> I started playing with qemu recently, mainly for work-related things
>>> that involve freebsd. I haven't tried it on my pvrusb2 box yet
>>> but I am tempted.
>>>       
>> I'd be curious to know how well that works.  The key factor will 
>> of course be how well qemu handles USB support.
>>     
>
> I tried qemu on my tv box today. Making it work was unfortunately
> not as straight-forward as I would have liked. The first problem
> was that I had to compile qemu from source on that box, and the
> qemu release won't compile with gcc-4. So I used the svn version
> instead, and there the second problem showed up: usb support is
> broken in the current svn. But I was able to fix that (and a patch
> is in the pipeline) and after some fumbling with the qemu control
> monitor I managed to redirect my 2040:2400 device to the guest OS.
> At that point the drivers were loaded, the firmware was installed,
> and the v4l devices were created. Then I tried capturing with
> "cat /dev/video0" and it sort of worked. The sound was ok but
> about half of the video frames were missing so the picture was
> jerky in mplayer (when played later on another machine).
>
>   

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.

Xavier