Re: [Qemu-devel] EHCI USB regression in 1.2.0 - ehci_state_fetchqtd() asserting

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 10/02/2012 05:26 PM, Shawn Starr wrote:
> On Monday, September 24, 2012 10:38:57 AM Shawn Starr wrote:
>> On Monday, September 24, 2012 04:36:15 PM Hans de Goede wrote:
>>> Hi,
>>>
>
> Hello,
>
> Reopening this issue with usb-host stalling now
>
> ehci warning: guest updated active QH
> USBDEVFS_DISCARDURB: Invalid argument
> USBDEVFS_DISCARDURB: Invalid argument
> husb: leaking iso urbs because of discard failure
>
>
> Now with qemu-XXX-1.2.0-12.fc18.x86_64
>
> if I have webcam open, it will stall and not resume. This is with usb-host
> directly.
>
> Shall I enable debugging again?

Hmm, this likely is caused by too high latencies in your system,
which are caused in turn I believe by you running an F-18 kernel which
has various debugging options enabled inside the kernel which can
cause significant latencies. I've spend 1.5 days tracing this very
same issue down in the past. So please first of all make sure that you're
running a kernel without debugging options enabled, either the latest
F-18 build from koji:
http://koji.fedoraproject.org/koji/buildinfo?buildID=358570

or an F-17 kernel, almost all the F-18 "rc" kernels have debugging enabled
and thus cause significant latency issues.

If you can reproduce this with a kernel without the debugging options,
then we can investigate this further.

Regards,

Hans