[sane-devel] Timeouts: usb_reset seems necessary to avoid bulk timeouts.
Karl Heinz Kremer
khk@khk.net
Thu, 10 Jun 2004 05:36:52 -0400
I'm also reading sane-devel, so no need to take a detour with
any Epson backend related information :-)
I've never experienced any of the problem you describe, and I've
been running a 2.6.x kernel for some time now (SuSE 9.1 beta versions
and the final SuSE 9.1).
I've tried this with two different USB controllers (USB-1.1 and high
speed USB-2) with a number of different Epson scanners.
Karl Heinz
On Jun 10, 2004, at 12:02 AM, Olaf Meeuwissen wrote:
> Hi Tom,
>
> I am the lead developer of iscan and the sane-epkowa backend that
> comes with it. Farideh has also contacted me about your issue, but I
> think that my reply is better sent to sane-devel (at least it'll be
> archived :-).
>
> Tom Schutzer-Weissmann <misc@tomweissmann.org> writes:
>
>> I had problems using the Epkowa libraries (libsane-epkowa) and the
>> iscan frontend with my usb scanner in kernel 2.6.
>>
>> The scanner was closed after each operation. Once closed, nothing
>> could be read from it, and I got lots of BULK TIMEOUTs, although there
>> were no errors when the device was reopened.
>
> Sorry to say, but I can't reproduce your problem. I've tried with a
> GT-8200 (aka Perfection 1650) on SuSE 9.1 and Debian (testing). FWIW,
> the version of relevant packages:
>
> SuSE Debian
> iscan 1.8.1-0.redhat.8.0 1.8.1-0.redhat.8.0
> sane 1.0.13-73 --
> libsane -- 1.0.14-2
> libusb 0.1.8-31 --
> libusb-0.1-4 -- 0.1.8-11
> kernel-default 2.6.4-52 --
> kernel-image-2.6.6-1-686 -- 2.6.6-1
>
> with the note that I compiled iscan from sources on Debian.
>
> Can you give more information about your setup? Things like scanner
> and distribution used as well as version of relevant software might
> help me in reproducing your problem.
>
> When you say that "Once closed, nothing could be read ...", do you
> mean the calls to sanei_usb_close? I've looked at the debugging USB
> output and don't see any bulk timeouts. My system logs also show
> nothing.
>
>> By modifying the code so that usb_reset() was always called before
>> usb_release_interface() and usb_close(), I solved the problem.
>
> The epkowa backend does not call the usb_* functions directly, so I
> presume you have been mucking around in sanei_usb, right? This would
> seem to indicate that you think the problem is not specific to the
> epkowa backend. I see below that you also get BULK TIMEOUTs with the
> epson backend. Both backends share a lot of code, so this is not an
> indication that your problem is not backend specific.
>
> Has anyone seen this with other backends?
>
>> For libusb developers, my question is, should this be the case? There
>> is nothing in the API docs to indicate that it's necessary - perhaps
>> it is self-evident?
>>
>> Farideh - in the belief that you are a point of contact for Epson
>> developers - could you make them aware of this issue, if they aren't
>> already.
>
> I read sane-devel ;-)
>
>> I think this is relevant to SANE because although I had some success
>> scanning with xsane and xscanimage, using the libsane-epson libraries,
>> I still got timeouts if I closed, say, xsane, and then restarted it -
>> for lack of a usb_reset() I believe.
>
> I have no problems closing iscan and restarting it (for the setups
> listed above).
>
>> Apologies if this is old news. Tom SW
>
> Hope this helps,
> --
> Olaf Meeuwissen EPSON KOWA Corporation, PF1
> FSF Associate Member #1962 sign up at http://member.fsf.org/
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> Penguin's lib! -- I hack, therefore I am -- LPIC-2
>
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