RE: [hpoj-devel] hpoj-0.6 feedback

[PASCHAL,DAVID (HP-Roseville,ex1) <dav...@hp...>]

Hi, Daniel.

> It always happens on large scans (> about 2MB)--every time.  
> I haven't checked
> to see if it always happens at the same byte number or not, 
> but it always occurs
> on a large scan.  Scanning small images (< about 2MB) seems 
> to work fine.  I
> haven't tried enough small scans in a row to see if it's only 
> a problem with
> large scans, or if it's a problem with total data transfer 
> since the module was
> loaded.
In the "large scan" cases where it breaks every time, it would still be
helpful for me to know what scan settings you use:
- preview or non-preview
- lineart, halftone, grayscale, or color
- resolution
- geometry settings (unless scanning the whole page)
If I know exactly what you do I might have a better chance of reproducing
the problem.  In some cases different values for the above options can
change the timing due to changing whether the scanner or the PC is the
bottleneck.

> If I get the right debug incantations though, I can log 
> everything up to the
> point the module hangs and try to backtrack from there.  What 
> do you think would
> be the appropriate debug parameters so that I don't get too 
> much info, but still
> get enough?
When I turn on debug output for the kernel drivers I generally use
"debug=15" for ieee12844.o and/or "debug=1" for ieee12844pp.o".  I would say
start with only logging ieee12844.o, and then try logging both.  If you want
you could also try only logging ieee12844pp.o.  Note that the output will
appear on the console (which can't be redirected to a file), and it should
also show up in syslog (possibly /var/log/messages) if syslog is configured
correctly.

> OK.  I thought HP might have provided a list somewhere.
HP did provide some documentation before I joined the project, but it mainly
addressed the OfficeJet 300/500/600/700 series.  The list of OIDs recognized
by "hpo" came directly from that information, so there isn't really more to
add.

> Is it possible to just
> run through a list of numbers, or do the OID values get sent as strings?
An OID is actually a list of numbers (for example, 1.1.2.20.2.1.1 is
OID_STATUS_MSG_LINE1_PART1).  Ultimately it is transferred as a string of
bytes (binary, not ASCII, and of course no periods).  In a given device the
set of all supported OIDs (the MIB) is actually more of a tree structure, so
it's not easy to just try all possible values.  PML (and SNMP) also have a
"get next" operation, where you give it an OID and it replies with the next
supported OID and its value.  I haven't played around with this feature
much, though.

David