[hpoj-devel] lots of ptal-mlcd fixes

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

Hi,

Tonight's major ptal-mlcd changes include the following:

- "scanimage --test" should now work properly on the OfficeJet Pro
1150/1170/1175, OfficeJet R series, and PSC 500.  Daniel and Obi-Wan,
would you please verify that this now works for you, since you both saw
this failure?

- Added the following "special" services, which you can access with a
command like "ptal-connect mlc:usb:0 -service <serviceName>":
PTAL-MLCD-CONSOLE -- the debug console, if -remconsole was specified, already
accessible as "-socket -1".
PTAL-MLCD-PID -- the process ID.
PTAL-MLCD-CMDLINE -- the command line parameters.
PTAL-MLCD-DEVNODE -- the assigned /dev/usb/lpX device node, if any.
PTAL-MLCD-DUMP -- a dump of major data structures.
For example, you can kill ptal-mlcd for a specific device by saying something
like "kill `ptal-connect mlc:par:0 -service PTAL-MLCD-PID`".

Lots of miscellaneous code cleanups:
- Fixed the data-flow code paths so channels can't starve each other or
the debug console (if active).
- Cleaned up the warning log messages which sometimes appeared while scanning
on USB.
- All the other gory details can be found in the checkin comments.

There were some pretty far-reaching changes in this checkin, and I somehow
managed to break a lot of things while making these changes.  :-)  It should
all be fixed now, but I would appreciate it if people could do some print
and scan testing and let me know if anything odd happens, such as error or
fatal error messages, especially about bad states or invalid file
descriptors passed to fdRegister().

David