[sane-devel] umax_pp slow
Thu, 30 Sep 2004 21:00:10 +0200
On Wed, Sep 29, 2004 at 04:05:33PM -0500, Joe Henley wrote:
> I got the lastest version (patch) of umax_pp working on the latest
> version of Sane and XSane; those, in turn, run on Red Hat 9 Linux. I'm
> using an Astra 2000P scanner. The umax_pp config file uses: port
> /dev/parport0. The BIOS is set for EPP (ECP is not available in my BIOS).
> When I try to scan something at 300 DPI the scanner does a "four steps
> forward, one step back" dance. It takes a long time to complete the
> scan. If I scan at 150 DPI, the scanner does it all in one pass,
> without the "dance." If I dual boot into Win98 and use the scanner at
> 300 DPI, no dance.
> Does anyone know how to get my scanner to scan at 300 DPI quickly, in
> Linux -- like it does in Win98?
> Thanks for any suggestions!
> Joe Henley
faster scan speeds are reached with direct hardware access.
You can change this in the umax_pp.conf file, set the 'port' option
to the address of your parallel port.
By default, the umax_pp backend tries to use ppdev which does
an extra data copy form kernel to usespace and slow down scans. You can
also check that your parallel port allows 4 bytes writes. In a command
shell do 'export SANE_DEBUG_UMAX_PP_LOW=1', then do 'scanimage -L 2>log'.
When finished search in it for a line :
[umax_pp_low] 32 bits EPP data transfer
If you don't have it, it is certainly because your parallel port
is not correctly set by the kernel. In this case, using direct hardware
access may get around it.
P.S. Got the mail you sent me, but couldn't answer because
http://security.rr.com blocked my mail.