Re: [hpoj-devel] (Unofficial patch) 2nd patch to hpoj for 2.4

[<pa...@rc...>]

> >BTW, there is still another problem with the kernel drivers which causes
> >more-or-less random lockups of the client process, for example, when doing
> >a large scan.  If you're able to do anything about that or even just have
> >any ideas on what could be causing it, it would be much appreciated too. 
> :-)
> 
> I've spent a little time reaquainting myself with the code, and I think I
> can take a shot at this.  Fortunately (maybe), it hangs reliably with
> debugging turned on, suggesting a timing issue (interrupt scheduling
> conflicts maybe?).
> 
> I want to start with a small scan like maybe 'scanimage --test', but I don't
> know how the protocol works.  How can I find out what the data exchange
> should look like between the driver and scanner during a scan?  Something
> like a step-by-step explanation would be best.  A dump of the incoming and
> outgoing data would also help.  Then I can compare what I'm getting with
> what I should be getting and hopefully find out where the error is creeping
> in.

Hi, Daniel.  There is a little section at the end of SCAN-HOWTO telling how
to turn on debug output for the SANE HP backend and for PTAL:
>        export SANE_DEBUG_HP=128
>        export PTAL_DEBUG=2
You'll probably want to have HP's SCL documentation handy (available from
http://www.hp-developer-solutions.com, free registration required).  If you
want you can e-mail the output to me (pa...@rc..., not the mailing
list) and I'll take a look at it too.

After I wrote that last paragraph I re-read your question and realized I
didn't answer it.  :-)  It sounds like you're wanting debug output from
some successful runs.  "scanimage --test" may work OK for you (try it and
let me know if even that gives you trouble).  Let me know exactly what
operations you want debug output for and I'll send it to you.

David