Re: PATCH: fix the barrier IDE detection logic

[Jens Axboe <axboe@suse.de>]

On Fri, Sep 03 2004, Bartlomiej Zolnierkiewicz wrote:
> 
> On Tuesday 31 August 2004 18:50, Alan Cox wrote:
> > This fixes the logic so we always check for the cache. It also defaults
> > to safer behaviour for the non cache flush case now we have the right bits
> > in the right places. I've also played a bit with timings - the worst case
> > timings I can get for the flush are about 7 seconds (which I'd expect
> > as the engineering worst cases will include retries)
> > 
> > Probably what should happen is that the barrier logic is enabled providing
> > the wcache is disabled. I've not meddled with this as I don't know what
> > the intended semantics and rules are for disabling barrier on a live disk
> > (eg when a user uses hdparm to turn on the write cache). In the current
> > code as with Jens original that cannot occur.
> 
> I think that logic is reversed here, I guess it should be: enable barrier
> if user enables wcache and disable it if user disables wcache.

There's no need for changes, ide_queue_flush_cmd() handles this fine
right now.

-- 
Jens Axboe