Re: [Linux-usb-users] USB scanner issue (Was: Re: Beaver in Detox!)

[Henning Meier-Geinitz]

Hi,

On Fri, Nov 28, 2003 at 11:26:25AM -0700, Tom Rini wrote:
> On Wed, Nov 26, 2003 at 12:55:00PM -0800, Linus Torvalds wrote:
> 
> [snip]
> > I give you "Beaver in Detox", aka linux-2.6.0-test11. This is mainly
> > brought on by the fact that the old aic7xxx driver was broken in -test10,
> > and Ingo found this really evil test program that showed an error case in
> > do_fork() that we had never handled right. Well, duh!
> 
> I've found an odd problem that's in at least 2.6.0-test11.

Did it happen in older versions of Linux? I haven't heard of any
similar bug reports until now.

> I've
> reproduced this twice now with an Epson 1240 USB scanner
> (0x04b8/0x010b).  What happens is if I run xsane from gimp, acquire a
> preview, start to scan and then cancel, the scanner becomes
> unresponsive.

This may be a bug in the plustek backend which supports that scanner.
The cancel handling is pretty complicated with some scanners.

> If I try and quit xsane, it gets stuck.

That sometimes happens with other scanners, too. E.g. some don't like
to get a "stop scan" command in certain situations. They just hang
after that command and further commands run into the USB timeout.

> Unplugging /
> replugging and then trying to kill xsane locked the machine up hard.

Well, obviously that should't happen. But it's really hard to debug
without any oops. There was a bug in the scanner driver that occured
when a device was open, then unplugged and then an application wrote
to it. But it's fixed since some time.

Does the freeze also happen if no other USB devices are attached? I guess
working without a keyboard is not that easy but it may be worth a test.

Otherwise I don't have any ideas.

Bye,
  Henning
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