Re: [Qemu-devel] usb_linux_update_endp_table: Broken pipe

[Pantelis Koukousoulas]

> Unfortunately qemu fails to add my USB scanner to the guest:
>
> $ qemu -M pc -m 256 -smp 1 -name winders -boot c -drive 
> file=winders.img,if=ide,index=0 -usb -usbdevice tablet -usbdevice 
> host:043d:00bb
> husb: open device 4.6
> husb: config #1 need -1
> husb: 3 interfaces claimed for configuration 1
> husb: grabbed usb device 4.6
> usb_linux_update_endp_table: Broken pipe
> Warning: could not add USB device host:043d:00bb

Yes, this is the typical symptom

> I note a workaround in this post and I confirm it works (FSVO):
>
> http://ubuntuforums.org/showpost.php?p=5744172&postcount=5
>
> Any thoughts as to what a proper fix might be? It would be good to not
> have to rebuild qemu with the workaround every time I update my system.

I think it would be worth to just merge this patch. I asked myself a few days
ago, but it seems to be a period where qemu moves quite fast (with the move
to git and all) and there is no time to review usb patches.

Perhaps we should have a usb-specific git tree so that we can test/fix all
usb-related patches that are in limbo right now and occasionally propose
merges.

>
> The above workaround works in that it allows Windows to detect the
> scanner but there seems to be some other issue because the Windows
> scanner app can initiate scans but comes up with a generic error dialog
> half way through. Unsure if this has anything to do with qemu.

There could be several reasons for that. Note that your device is also a bit
on the peculiar side, in that it actually has 3 interfaces (and thus 3 drivers).
It could be also a speed/stall problem but this is unlikely since max's work
has made the usb backend reasonably fast these days.

Cheers,
Pantelis