Re: How to set hdparms for ide-scsi devices on devfs?

[Jeremy Jackson <jerj@coplanar.net>]

Eduard Hasenleithner wrote:

> Sorry, if this issue was already discussed in lkml. I didn't find
> a reference to this at www.geocrawler.com
>
> My Problem:
> I want to set the unmaskirq and dma -flag for my ide cd-recorder.
> The Problem is, that devfs creates no ide device, but only
> the /dev/scsi/../{cd,general} devices are created. And hdparm
> don't accepts this devices for setting the ide-parameters.
>
> My current workaround is to create a /dev/hd? device "by hand"
> at system startup. This is not very beautiful. Furthermore, if
> the device numbers in devfs are deactivated, this won't work
> anymore.
>
> I can live with my current solution. But i would be very happy
> if someone can present a clean solution.
>
> I posted this message intentionally not on the devfs mailing list
> as i think this problem is related to accessing the same device
> through different /dev entries. Under devfs, the /dev/ide/...
> device node gets allocated after the corresponding ide-xx.o has
> been loaded. But this is not possible with ide-scsi claiming
> the device :(
>
> Thanks in advance

workaround - before ide-scsi is loaded in boot sequence
(finding is left as an exercise to the reader :) do:

modprobe ide-cd
hdparm -u 1 -d 1 /dev/xxx
rmmod ide-cd

might have to do near top of /etc/rc.d/rc.sysinit under redhat,
but this is good since problems will happen before root filesystem
is remounted read-write, so any problems with hdparm settings
won't mess up disk.