Subject: Re: disks write-back cache
To: Manuel Bouyer <>
From: Sean Davis <>
List: tech-kern
Date: 04/27/2003 09:57:11
On Sun, Apr 27, 2003 at 03:10:42PM +0200, Manuel Bouyer wrote:
> On Sat, Apr 26, 2003 at 12:22:02PM -0400, Sean Davis wrote:
> > On Sat, Apr 26, 2003 at 06:05:27PM +0200, Manuel Bouyer wrote:
> > <snip>
> > > So, should I add a check to the sd or wd drivers to print a warning (dependant
> > > on a compile-time option) when a disk with write-back cache enabled is probed ?
> > > Or maybe put it in the filesystem layer, at mount time ?
> > 
> > I think this would be useful. However, I think it would be much more useful
> > if you would add dkctl(8) support to wd, so those of us who don't have scsi
> > can disable write-back cache if they so desire.
> I added it yesterday :)

doesn't appear to work. I tried: dkctl wd0 setcache w, and got a:
pciide1:0:0: lost interrupt
  type: ata tc_bcount: 0 tc_skip: 0

and dkctl getcache still reported writeback cache as enabled.
according to the dkctl manpage, my usage was incorrect. however, the command
according to the dkctl manpage to disable writeback cache would be dkctl wd0
setcache r, but this gives me:
dkctl: /dev/rwd0d: setcache: Operation not supported


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