On Fri, 26 May 2006, Lauri Pirttiaho wrote:
When using libusb method in sanei_usb the behavior of
sanei_usb_read bulk seems to be that in responese to
NAK (errno -ETIMEDOUT, strerror saying Resource
temporarily unavailable, which means the device
can not temporarily provide more data)
the sanei_usb_read_bulk calls usb_clear_halt
and then returns SANEI_STATUS_IO_ERROR.
certain fujitsu scanners have trouble resetting the data0/1 usb toggle
properly, generally at the first command after the scanner is opened.
libusb returns to sane -ETIMEDOUT, and errno is EAGAIN (Resource
temporarily unavailable).
the clear_halt does not help, i have tried both ways.
Now because of the usb_clear_halt there is no longer access
to the errno so this particular reason for the IO error
can not be distinguished from others after sanei_usb_read
bulk returns.
i do not understand this- errno still exists on my system, even after the
clear call? are you saying that you want the negative read_size error
returned?
The solution in Avision backend seems to be that the
errors from sanei_usb_read bulk are completely ignored and
the function is called repeatedly until all data has been
read. A temporary solution but maybe not the best one.
for some scanners, perhaps the only method that works.
I would propose changing the behavior of sanei_usb_read bulk
so that in the case of NAK (resource temporarily unavailable)
the size is returned as 0 and the return value is set
either to SANE_STATUS_GOOD (read OK, just no data
at this moment) or SANE_STATUS_BUSY (device can not
respond right now). Both will work even though probably
the latter one is more in line with the meaning of USB NAK
in this case.
what about all the other possible error codes that might be returned? what
about using a callback mechanism like sanei_scsi does for sense data? then
the backend can tell exactly what sane status it wants returned.
unfortunately, i am not sure about the returns from non-libusb libs.
allan
With best regards,
Lauri Pirttiaho
Oulu
Finland
...
Luukku Plus paketilla p??set eroon tila- ja turvallisuusongelmista.
Hanki Luukku Plus ja helpotat el?m??si. http://www.mtv3.fi/luukku
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From azummo-li...@towertech.it Sun May 28 23:44:36 2006
From: azummo-li...@towertech.it (Alessandro Zummo)
Date: Sun May 28 23:46:03 2006
Subject: [sane-devel] Re: Epson CX11 network scan support?
In-Reply-To: 20060523083805.ga29...@apartia.fr
References: 20060522105248.gb28...@apartia.fr 87hd3habf9@geek.avasys.jp
20060523083805.ga29...@apartia.fr
Message-ID: 20060529014436.2dbd07ed@inspiron
On Tue, 23 May 2006 10:38:05 +0200
Louis-David Mitterrand vindex+lists-sane-de...@apartia.org wrote:
IIRC, Alessandro Zummo hacked up something to make scanning via TCP/IP
work. See
http://lists.alioth.debian.org/pipermail/sane-devel/2006-January/015986.html
for details.
Thanks, this looks promising.
Will this work soon be integrated into sane?
Hi,
I've been unable to work on the driver recently. I'd say the job is half done,
because comms works fine but a lot of testing needs to be made to fully
support the scanner.
I've posted the generic network code in this ml, but I don't think
it has been included in SANE yet. This is a required step.
The epson2 driver I've posted uses this code to communicate
to the scanner.
It would have been easier if Epson had released the specs. :)
If I can find a few people that can code some bits, the driver could
be completed in a decent timeframe.
--
Best regards,
Alessandro Zummo,
Tower Technologies - Turin, Italy
http://www.towertech.it
