Re: Problem in IDE Disks cache handling in kernel 2.4.XX

Benjamin Herrenschmidt (benh@kernel.crashing.org)
10 Jan 2003 12:07:56 +0100


On Fri, 2003-01-10 at 12:37, Alan Cox wrote:

> > And by the way how are powered off the IDE drives ?
> > Because a FLUSH CACHE or STANDY or SLEEP is MANDATORY before powering off the
> > drive with cache enabled or you will enjoy lost data
>
> IDE disagrees with itself over this but when we get a controlled power
> off we do this. The same ATA5/ATA6 problem may well be present there
> too. I will review both

I did fix a data loss problem with some PPC laptops that way too, that
is just before shutdown and just before machine sleep, sending a STANDBYNOW
command. In the case of machine sleep, I make sure not to accept any more
request (mark the hwif busy) after that and until machine wake up (at which
point I do a full hard reset or poweron reset of the drive).

Ben.

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