Date: Fri, 13 Nov 2009 21:30:07 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Robert Hancock <hancockrwd@gmail.com>,
       "linux-kernel" <linux-kernel@vger.kernel.org>,
       ide <linux-ide@vger.kernel.org>, Jeff Garzik <jgarzik@pobox.com>
Subject: Re: [PATCH] libata: remove experimental tag on PATA drivers
Message-ID: <20091113213007.774e75e3@lxorguk.ukuu.org.uk>
In-Reply-To: <200911132039.06929.bzolnier@gmail.com>
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	<200911131715.24377.bzolnier@gmail.com>
	<20091113182515.38fb3793@lxorguk.ukuu.org.uk>
	<200911132039.06929.bzolnier@gmail.com>
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> > Not experimental as we default to not doing ATAPI DMA. Glancing over the
> 
> Which is a regression compared to the "old IDE" driver.

And given the two drivers show the difference when exactly the sequence
of I/O writes/reads occurs one that nobody plans to worry about as its
clearly some kind of hardware timing issue.

> > code I notice the ALI C2/C3 workaround probably wants adding to the old
> > driver as it can do nasty things otherwise. (See the reset function in
> > the pata_ali driver)
> 
> Please let the driver's maintainer know about it.
> 
> One would wonder why workaround hasn't been back-ported to stable driver

It's in the stable driver, might not be in drivers/ide. The note about it
being missing was posted out to various people at the time so I guess it
got missed

> > > PATA_CMD64X: EXPERIMENTAL
> > > - potential data corruption issues remains unfixed for CMD64[3,6]
> > 
> > Patch in testing, and unlike the old IDE one it doesn't cripple the
> > controller but implements the proper workaround in full including
> > permitting parallel PIO command streams. I'll push that back through
> > stable once done.
> 
> This patch is way too complex and risky for -rc, let alone -stable.

How would you know - I've not posted it yet ? And btw I don't plan to
post it for the -rc. Nor would simply posting a serializing hack fix it.
It might make it less likely to occur but that isn't a fix.

> > it. Trivial and fixed.
> 
> I can't see a fix anywhere but I'll assume that I can't look for it
> properly (I'm really sorry for it).

Fixed as in I fixed it now. Which is why I just noticed the old IDE ones
are buggy. I'll add it to the next patch sets for Jeff, along with the
Toshiba driver and some other bits.

Alan


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