[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] USB continuous reset / unplug cleanup not done properly

From: Erik Rull
Subject: Re: [Qemu-devel] USB continuous reset / unplug cleanup not done properly
Date: Mon, 19 Dec 2011 18:31:24 +0100
User-agent: Mozilla/5.0 (Windows NT 5.1; rv:8.0.1) Gecko/20111121 Firefox/8.0.1 SeaMonkey/2.5

Hi Gerd,

Gerd Hoffmann wrote:

1) Devices get resetted again and again on the host side and do not work
properly on the guest side - they work fine on the host side outside qemu.

I see those too.  Not clear what is going on here.  usbfs requests seem
to get stuck now and then for not-yet known reasons.  Sometimes they
finish after a few seconds.  Sometimes they get stuck long enougth that
some timeout within the guest fires and the guest resets the device.

Is it possible to increase either the timeout periods or "block" the USB device during it is in use by the guest, so that usbfs does not want to reset it?

I see those with a F16 guest which polls the usb stick with
test-unit-ready requests.  Letting it run idle produces a ...

    usb 1-6: reset high speed USB device number 3 using ehci_hcd

... log line line in the guest now and then.  Tried to write a small
reproducer (tool constantly sending test-unit-ready via usbfs), but that
one works just fine without any hangs.

Is it possible to trace the USB requests at this level? Maybe there is a possibility to figure out why the reset happens.


Any idea about the second point regarding the remaining devices in the info usb list?

Best regards,


reply via email to

[Prev in Thread] Current Thread [Next in Thread]