Re: [hpoj-devel] OJ 700 Progress

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

James Klicman wrote:
> I have succeeded in scanning BILEVEL_THRESHOLD/NO_COMPRESSION
> and then creating a viewable .pgm file with the data.
> 
> Unfortunately, it only seems to work a few times in a row then it
> starts to hang each time during an MlcCon_read.
> 
> Scanning GRAYSCALE_256/NO_COMPRESSION results in a hang everytime.
> 
> Scanning COLOR_24_BIT/NO_COMPRESSION results in FixedHeaders with no
> RasterData and then hangs.
Hi, James.  Congratulations on getting at least BILEVEL_THRESHOLD scanning
working.  :-)  What exactly is a .pgm file?

> It almost seems like there is a certain amount of data that will
> pass through the scan channel without problem. After that it starts
> to hang. This might explain why I can have a few successful scans
> at BILEVEL_THRESHOLD before problems occur, and not get through
> a full scan at GRAYSCALE_256 which would transfer 8 times the amount
> of data.
That's quite possible.  You might be able to test that theory by cutting
out a short piece of paper (still 8.5" wide) and doing an 8- or 24-bit scan
on that, because the scan should stop when it reaches the end of page.  Just
don't make it too short, or it might get lost in the scanner and cause paper
jams.  You could also try taping several sheets together and doing a 1-bit
scan on that, but again be careful when taping not to leave any sticky spots
that could cause a jam.

> Could you please explain the current problem with multi-channel
> communication? I am wondering if it is something I should look into
> or wait for/help with the new drivers.
I never got around to looking into it, but you can also reproduce it by
printing while running xojpanel, or vice versa.  I'm fairly sure it's a
bug in ieee12844.c, not ieee12844pp.c.  You're welcome to look into it if
you're interested in digging around in kernel space, especially if it's
preventing you from making progress at the moment.

> Do you have any idea when the new drivers you're working might be ready?
It's working fairly well now (I can print and scan on a USB-connected K80).
However, I'm still trying to negotiate release of this code with my
management, because I leveraged a significant amount of HP-proprietary code.
I'm optimistic that I'll be able to resolve it, but I can't say when at this
point.  On the technical side, I still need to finish adding PML support to
PTAL and the new driver before PML scanning will work through it.

David