Re: [Qemu-devel] [PATCH 1/7] usb: remove old usb-host code

[Jan Kiszka]

On 2013-10-09 13:42, Gerd Hoffmann wrote:
>   Hi,
> 
>>>> Only very recent distros fulfill the need of >= 1.0.13, so you naturally
>>>> fall back to this code. I just realized that even the factory build of
>>>> OpenSUSE is still on libusb-1.0.9. Current Ubuntu versions are on 1.0.12
>>>> at best. Didn't check others so far.
>>>
>>> Ouch.  The 1.0.13 release is one year old by now.
>>>
>>> Fedora 19 is at 1.0.16 btw.
>>>
>>>> So isn't this step a bit too early?
>>>
>>> There is always the 'git revert' option in case it turns out there are
>>> too many issues ...
>>
>> So what to do? Do you expect all the other distros to catch up regarding
>> libusb until QEMU 1.7 is released?
> 
> They will update once they figure this is needed for qemu 1.7 :)
> Updates will probably not yet be available at release time though.
> 
> If we revert, thereby continue fallback to the old code, chances are
> high that nothing happens and we'll face the same issue for qemu 1.8.
> 
> Given that there are some known issues in the host-linux code which are
> fixed in host-libusb I really want get rid of it.

OK, then here is the first issue I ran into while trying libusbx (git
head, i.e. 1.0.17+: The new stack causes significant latency issues that
makes it almost unusable for pass-through of USB audio devices (some
headset in my case). Reverting usb-linux and disabling libusb over QEMU
git head makes things work again. I'll have to stick with this for now
as it is affecting my work environment.

Any spontaneous ideas how to analyse or even resolve this?

Jan

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