Re: [PATCH,RFC] make ide-scsi more selective

Willem Riede
2001-08-23T00:11:47Z

Alan Cox wrote:
>
> > I've been rather annoyed by a dual problem in the ide-scsi setup:
> > during initialisation, ide-scsi will claim ALL currently unassigned
> > IDE devices. This is a problem in modular setups, since there's
> > no guarantee that currently unassigned devices actually are intended
> > for ide-scsi.
>
> The real problem is that the drivers are claiming resources on load not
> on open. Why shouldnt I be able to load ide-cd and ide-scsi and open either
> /dev/hda or /dev/sr0 but not both together ?
>
Ion Badulescu wrote:
>
> On Wed, 22 Aug 2001, Nicholas Knight wrote:
>
> > Here's an end-user perspective for you... I just spent 2 days trying to
> > figure out how to use my CD-RW drive to read when using ide-scsi, before
> > I finnaly realized that I had to do it by disabling ATAPI CD support and
> > enabling SCSI CD support..
>
> Just doing hdX=scsi would have been enough, however. Except it doesn't
> work (currently) if ide-scsi is a module.
>
Well, at least on my system (RH 7.1) in rc.sysinit there's a fragment
that checks if ide-scsi is asked for and if so loads ide-cd first, so
it can grab CD drives that are not targeted for scsi emulation.

Personally, I've added a modprobe of ide-tape there so that ide-scsi
can't grab any tape drives it is not supposed to either.

> I agree with Alan that the problem is the grab-on-load strategy that
> ide-scsi (and ide-cd for that matter) uses. I am willing to look into
> changing that to grab-on-open but I'm not sure if the change is an
> appropriate one for a stable series kernel -- it looks pretty non-trivial.
>
Right. And it is not limited to ide-scsi but impacts drivers that
connect to ide-scsi such as the osst tape driver I maintain which
would have to allow a device to be ht0 and osst0 at the user's choice...

Regards, Willem Riede.