Forcing use of sd driver on Suse 10.3 (2.6.22)

Forcing use of sd driver on Suse 10.3 (2.6.22)

[Bill Adair]

I have a device reported as below. It is a PCMCIA card reader with
SCSI-2 connections. I know the device can work as a direct access device
when flash memory is present as I have connected it to an Akai sampler
which can read the card. I am assuming here the sampler's SCSI stack is
not very complex and is just ignoring the device type.

[2:0:6:0]    process MPL      MC-DISK-E[0]     3.9a  -         /dev/sg2
[2:0:6:1]    process MPL      MC-DISK-E[0]     3.9a  -         /dev/sg3
[2:0:6:2]    process MPL      MC-DISK-E[0]     3.9a  -         /dev/sg4
[2:0:6:3]    process MPL      MC-DISK-E[1]     3.9a  -         /dev/sg5
[2:0:6:4]    process MPL      MC-DISK-E[1]     3.9a  -         /dev/sg6
[2:0:6:5]    process MPL      MC-DISK-E[1]     3.9a  -         /dev/sg7
[2:0:6:6]    process MPL      MC-DISK-E[0]     3.9a  -         /dev/sg8
[2:0:6:7]    process MPL      MC-DISK-E[0]     3.9a  -         /dev/sg9

Is there any way under Linux of forcing use of the sd driver for a
device on the bus instead of sg?

TIA 
Bill

Re: Forcing use of sd driver on Suse 10.3 (2.6.22)

[Stefan Richter]

Bill Adair wrote:
> Is there any way under Linux of forcing use of the sd driver for a
> device on the bus instead of sg?

The INQUIRY data which the SCSI core gets from the device have to
indicate that the device implements SBC or RBC (is of peripheral device
type 00h or 0Eh).
-- 
Stefan Richter
-=====-==--- ---= -===-
http://arcgraph.de/sr/

Re: Forcing use of sd driver on Suse 10.3 (2.6.22)

[Bill Adair]

On Mon, 2008-01-14 at 19:31 +0100, Stefan Richter wrote:
> Bill Adair wrote:
> > Is there any way under Linux of forcing use of the sd driver for a
> > device on the bus instead of sg?
> 
> The INQUIRY data which the SCSI core gets from the device have to
> indicate that the device implements SBC or RBC (is of peripheral device
> type 00h or 0Eh).
I have altered the sd.c file by patching sd_probe to check for the
particular unit I have and accepting pdt 03h (Processor) as a valid
return and the unit works fine. 

I suspect the sd file is considered very important though (and I don't
know how many of these card readers exist) so I assume a patch is not
required ;-). Would there be another approach to creating a "driver" for
my Spyrus RD300 in it's guise as a card reader?

Bill

Re: Forcing use of sd driver on Suse 10.3 (2.6.22)

[James Bottomley]

On Thu, 2008-01-17 at 10:53 +0000, Bill Adair wrote:
> On Mon, 2008-01-14 at 19:31 +0100, Stefan Richter wrote:
> > Bill Adair wrote:
> > > Is there any way under Linux of forcing use of the sd driver for a
> > > device on the bus instead of sg?
> > 
> > The INQUIRY data which the SCSI core gets from the device have to
> > indicate that the device implements SBC or RBC (is of peripheral device
> > type 00h or 0Eh).
> I have altered the sd.c file by patching sd_probe to check for the
> particular unit I have and accepting pdt 03h (Processor) as a valid
> return and the unit works fine. 

That's a bit of a nasty.  We can't blindly attach sd to a processor
otherwise it will pick up all sorts of stuff its not supposed to bind to
(like scanners, enclosure devices and other initiators).

I suppose a firmware upgrade for the device to make it actually comply
vaguely with the spec is out of the question?

If not, there's a trick we do in scsi_scan.c for Toshiba CDROMS that
fail to set their type correctly (it's the code under BLIST_ISROM), we
could do the same for this device.  What are its inquiry strings?  And
does anyone have any clue whether it should be RBC or DISK type?

> I suspect the sd file is considered very important though (and I don't
> know how many of these card readers exist) so I assume a patch is not
> required ;-). Would there be another approach to creating a "driver" for
> my Spyrus RD300 in it's guise as a card reader?

James