[sane-devel] Out of Memory error when scanning at high DPI

[Mark Richards]

Thanks again for the prompt response.  I have one question:  when you say 
"your scanner breaks", do you mean that my physical scanner would be damaged?  
Or do you mean that the sane backend would be broken and I'd have to revert 
the change?  I'm willing to help get this driver working but I'm not in a 
position to risk damage to the scanner, unfortunately.

I have access to Windows XP, so if that can be of use for reverse-engineering 
the windows driver, I will help that way too.  Only problem is I don't have a 
dev environment in Windows so compiling software will be an issue.

Thanks,

Mark 

On Thursday 16 November 2006 22:45, Olaf Meeuwissen wrote:
> Mark Richards <mark.richards at gmail.com> writes:
> > Hi guys,
> > 	Thanks for the quick reply.  Attached is the output of attempting to
> > scan a 4x6 photo a few times at different settings (SANE_DEBUG_EPSON=25).
> >  Note that the out of memory error happens the instant I press the scan
> > button, not part-way through a scan or anything.  The scanner doesn't
> > even twitch.  It previews fine and scans at lower dpi/colour-depth
> > though.
>
> # OK, I see.
> # Somebody sure contributed an ugly hack just to get 4800dpi on the
> # 4990 to work ;-{  The epson backend only uses ESC based commands,
> # which implies that that you can't even set 4800dpi and even less
> # so the scan area you are using and have the device behave.  The
> # hack that went in probably shouldn't have ...
>
> Anyway, you can not scan wider than about 3.4 inches without avoiding
> this behaviour in sane-backends-1.0.18 on Linux.
>
> If you don't mind experimenting, you could try with a larger value for
> MAX_DATA in sanei/sanei_scsi.c but I have absolutely no idea what will
> happen.  In the best case things will "work", in the worst your
> scanner breaks.
>
> Hope this helps,
>
> > Thanks for the help,
> >
> > Mark
> >
> > On Thursday 16 November 2006 18:48, Olaf Meeuwissen wrote:
> >> Gerard Klaver <gerard at gkall.hobby.nl> writes:
> >> > On Thu, 2006-11-16 at 09:13 -0500, Mark Richards wrote:
> >> >> Hi,
> >> >> I have an Epson Perfection Photo 4990 (GT-X800) scanner connected by
> >> >> USB to my PC (Athlon 64 3200 1GB ram 5GB swap, FC5).
> >> >>
> >> >> scanimage --version : scanimage (sane-backends) 1.0.18 ; backend
> >> >> version 1.0.18
> >> >>
> >> >> Scanimage -L : device `epson:libusb:002:009' is a Epson GT-X800
> >> >> flatbed scanner
> >> >>
> >> >> I can scan fine at 1200dpi (16-bit colour) or 2400 (8-bit colour) but
> >> >> when I try to scan at anything higher I get an Out of Memory error.
> >> >> It is my understanding that scanning at 4800dpi should be possible
> >> >> with this scanner.  Any suggestions?
> >> >>
> >> >> Thanks,
> >> >>
> >> >> Mark
> >> >
> >> > With export SANE_DEBUG_EPSON=255
> >>
> >> You don't really want to do that at 4800dpi ;-).  It outputs a single
> >> line for every sample.  Use 25 instead of 255 for more useful output
> >> and mail me a (compressed) debug log.
> >>
> >> > and then start scanimage, check the logs for some info,
> >> >
> >> > For a A4 300dpi (24 bits, 8 bits per color) scan you get about 25Mbyte
> >> > of data, for 600dpi about 100Mbyte, for 1200dpi about 400 Mbyte, for
> >> > 2400dpi about 1600Mbyte.
> >>
> >> Mark mentions 1GB RAM ... if the frontend attempts to keep the whole
> >> scanned image in memory than at 4800dpi, 24bits he may be hitting the
> >> limit.
> >>
> >> Whereabouts does the out of memory occur?  Somewhere right at or near
> >> you start the scan or after you are more than halfway through the
> >> scan?
> >>
> >> Hope this helps,
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