Hi Adam,
I have no experience with the ppscsi/epst modules. So I can only give
you some hints about the hp-backend to see where the problems come from.
The main communication with the scanner seems to work. Otherwise you
wouldn't be able to scan a b/w image. Maybe the problems arise from the
large amount of data that must be read back from the scanner for
grey/color scans. To see if this is right you can try to do a grey scan
with low resolution or just a small part of the scan area.
If it is a problem with buffer overruns (scanner data not picked up fast
enough), you can try to scan in the complete image into memory before
passing to the scanimage frontend. You have to modify the hp.conf-file.
First of all, remove the line "scsi HP". If your scanner is
/dev/scanner, hp.conf should have
/dev/scanner
option enable-image-buffering
(If you would have the line "scsi HP" in the hp.conf, the additional
options would not be recognized).
You can also try to change the style how the image data is read back
from the scanner:
/dev/scanner
option enable-image-buffering
option disable-scsi-request
The image data is read back directly from the scanner without some level
of scsi-requests.
You can also try to modify some buffer size for the SCSI-handling.
export SANE_SG_BUFFERSIZE=32768
will set that buffer to 32 KB. You can try some smaller and bigger
values too.
I dont know if this could help to solve the problem, but you can try it.
--Peter
Adam Warner wrote:
>
> Hi Peter and all,
>
> (Please note this message has been carbon copied to the sane-devel and
> linux-parport mailing lists because of relevance. I think this is appropriate
> given that this may be a ppscsi issue).
>
> Thanks for your informative site about the SANE HP backend:
> http://www.kirchgessner.net/sane.html
>
> I have discovered that the ppscsi driver is not SMP safe (with my ABit BP6).
> But I've put that aside at the moment by recompiling the kernel in UP mode and
> I am trying to get scanimage to work.
>
> I am running sane 1.0.4 with a 2.4.2 kernel w/ppscsi 0.92 and epst modules
> incorporated.
>
> scanimage indeed works in 1 bpp mode:
>
> "scanimage -v > test" results in:
> scanimage: scanning image of size 2550x3507 pixels at 1 bits/pixel
> scanimage: acquiring gray frame
>
> (I can, for example scan as a tiff image and view it in The GIMP)
>
> However "scanimage -v --mode gray > test" results in:
> scanimage: scanning image of size 2550x3507 pixels at 8 bits/pixel
> scanimage: acquiring gray frame
> scanimage: min/max graylevel value = 255/0
> scanimage: sane_read: Error during device I/O
>
> The HP 5100C starts preliminary noises and scanning for a moment before halting
> and giving up with this error. I don't think the scanner is faulty because it
> passes all tests and does work in Windows 95 (I tested that out to make sure).
> I receive the same responses as Dave Gilbert using hpinq.
>
> Again if I try "scanimage -v --mode color > test":
> scanimage: scanning image of size 2550x3507 pixels at 24 bits/pixel
> scanimage: acquiring RGB frame
> scanimage: min/max graylevel value = 255/0
> scanimage: sane_read: Error during device I/O
>
> This is the resulting output in "test":
> P6
> # SANE data follows
> 2550 3507
> 255
>
> Every time I get the I/O error this is what turns up in dmesg:
> epst.1: Command abort not supported
> epst.1: Bus reset
>
> These messages are issued by ppscsi. They only appear to result because of the
> I/O error.
>
> I am new to C programming so I am just trying to obtain so preliminary
> understanding about what is going on and am happy to provide further
> information/testing that is necessary to flush out these bugs.
>
> How do I turn on verbose logging for ppscsi? If I add:
> options ppscsi verbose=4
> to /etc/modules.conf
>
> I then can't install the module but am told:
> /lib/modules/2.4.2/kernel/drivers/scsi/ppscsi.o: invalid parameter parm_verbose
>
> I did hear from Tim Waugh at Redhat that ppscsi is low priority right now
> (which I can understand).
>
> Regards,
> Adam
-- Peter Kirchgessner http://www.kirchgessner.net mailto:peter@kirchgessner.net-- To unsubscribe, send mail to: linux-parport-request@torque.net -- -- with the single word "unsubscribe" in the body of the message. --
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