[sane-devel] PIXMA: MX360 at 2400 x 1200 dpi

[ibu ☉ radempa ䷰]

Dated 2012-02-09 14:48, Rolf Bensch <rolf at bensch-online.de> said:
> It's not a big deal to fix this. From experience this is a problem in
> post_process_image_data or in one of the called functions shift_colors
> or reorder_pixels.
> 
> The attached patch switches image post processing off and extends max.
> resolution to 2400 dpi. Please have a look to the scanned images. Some
> scanners and / or resolutions need special pixel shifting functions. I
> also added a debug output for k.
> 
> We only need to look for gray and color scans. What results do you have
> with color scans?
> 
> Maybe you can debug this by yourself. You are also welcome to send your
> scanned images and log files to me.

Thanks. When I disable pixel_reordering analogously to MP220, then up to
1200 dpi gray and color scans are ok. At 2400 dpi however nothing is
scanned and I get

[pixma] read_image():reader task closed the pipe:0 bytes received,
143238656 bytes expected

which comes from pixma.c; more specifically, this line produces count=0:

count = read (ss->rpipe, buf, size);

read_image() is called from sane_read(), which provides ss ("sane
status", I guess) and itself gets it from a SANE_Handle which comes from
the frontend, AFAIS. I don't understand enough of the internals of sane
to know where to start debugging. - Hints are welcome.

ibu