[sane-devel] SCSI: error during device I/O

[Peter Kirchgessner]

Hi Doug,

from other replies and having a more detailed look at the error reports 
the problem what I was looking for seems to be related to some special 
Buslogic SCSI cards and 2.4.x kernels. The scanners (HP) worked well 
under 2.2.x, but not with 2.4.x. I am not quite sure which version of 
SANE was used.
Currently the only advice I can give is trying to use a different SCSI card.

--Peter


Douglas Gilbert wrote:

> Peter Kirchgessner wrote:
> 
>> Hello,
>>
>> some time ago problems have been reported with some 2.4.x kernels and 
>> SCSI-devices. What was working with 2.2.x, failed there with an "error 
>> during device I/O". The problem seemed to be a broken handling of 
>> SCSI-requests in the kernel (from mailing list: kernels 2.4.6, 2.4.10, 
>> 2.4.12 and 2.4.13).
>> Does anybody know if the problem has been fixed ? And if so, at which 
>> kernel ? The ChangeLogs don't tell me much.
> 
> 
> Peter,
> If the error from the sg driver is actually EIO then it
> indicates that the version 2 sg interface (based on the
> sg_header struct) is being used. One shortcoming of this
> interface was the difficulty of overcoming the default
> assumption of a SCSI command size based on its opcode
> (first byte). The SANE Canon backend was tripped up
> by that and supplied a patch to the sg driver. That patch
> probably hasn't worked (i.e. breaks when being applied)
> since lk 2.2.6 (over 3 years ago). The original sg driver
> (version 1) yielded EIO for just about every error it
> encountered!
> 
> Any recent SANE backend driver should be using the sanei
> layer which on a linux 2.4 series kernel will be using
> the sg version 3 interface. In this case EIO should not
> occur.
> 
> Doug Gilbert
> 
> 
> 
> 
> 
> 


-- 
Peter Kirchgessner
http://www.kirchgessner.net
mailto:peter at kirchgessner.net