Re: sd driver

[Douglas Gilbert <dougg@torque.net>]

Aldo Gavioli wrote:
> Hello All,
> 
> Hello All,
> I'm trying to attach one proprietary SCSI driver for optical disk on 
> kernel 2.6.
> I noted that if sd attach the same device before, my driver will never 
> be called in the probe function. How can I by-pass this situation ?
> If anyone can help me I appreciate very much.

Aldo,
Upper Level Drivers (ULDs of which sd is one) discriminate
on the basis of the peripheral device type returned by an
INQUIRY. Currently sd_probe() takes control of TYPE_DISK
(pdt=0x0) and TYPE_MOD (pdt=0x7 "Optical memory device")
and will soon take control of TYPE_RBC.

If the class of devices you are interested in is TYPE_MOD
then (at least for testing) just comment out that bit of
code in sd_probe().

The st and osst (tape ULDs) co-operate to do a finer
grain division of labour (see their respective *_probe()
functions). These ULDs show you one way of solving the
problem. Another way would be a kernel/module option
to sd (and possibly other ULDs) telling it to leave
device <h,c,t,l> (or better some world wide unique
identifier) alone.


As for Arjan's comment about extending sd to cope with
your class of devices, recent experience with RBC devices
indicates that such a move may not add to the coherency
of the sd driver.

Doug Gilbert