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    SubjectRe: [linux-usb-devel] USB snd-usb-audio wedges lsusb when unplugged while playing sound.
    Christopher Montgomery wrote:
    > On 7/22/06, Ian Stirling <> wrote:
    >> Config/... as my earlier message on USB - though with the bandwidth
    >> enforcement
    >> turned off so it actually plays sound, when plugged into the USB1 port.
    >> 2.6.17.
    >> Basically - playing sound with
    >> mplayer -ao alsa:device=hw=1 or whatever - and then unplugging the
    >> soundcard completely wedges lsusb/usb configuration, until the mplayer
    >> process is killed.
    > This sounds like the well known EPIPE problem in usb-audio and one I
    > intended to fix after dealing with the ehci scheduler.
    > enough system load on the machine that it may well even stop pinging.
    > Although the *machine* is not wedged, if this happens in a realtime
    > thread (eg, jack using a usb-audio device), it may well be hosed
    > enough to become unrecoverable.

    I just did it again, and the machine is >90% idle (PII/300), with
    mplayer doing:

    ioctl(5, 0x806c4120, 0xbffeffd0) = -1 ENODEV (No such device)
    write(2, "alsa-lib: pcm_hw.c:406:(snd_pcm_"..., 89) = 89
    write(2, "alsa-space: cannot get pcm statu"..., 50) = 50
    nanosleep({0, 10000000}, NULL) = 0
    ioctl(5, 0x806c4120, 0xbffeffd0) = -1 ENODEV (No such device)

    about 70 times a second.
    Of course, with other software, it may be different.
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