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From: Bruce Stenning <b.stenning@indigovision.com>
To: Mark Lord <kernel@teksavvy.com>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>
Date: Wed, 13 Apr 2011 17:13:07 +0100
Subject: RE: sata_mv port lockup on hotplug (kernel 2.6.38.2)
Thread-Topic: sata_mv port lockup on hotplug (kernel 2.6.38.2)
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> Yeah, I'm suspecting there's a loophole in the logic there somewhere.
>
> I dusted off the 6041 reference card I have here, and played with the cables for a while.  Managed to > get one port to stop responding to hot plug fairly quickly, though I'm not sure how/why.
>
> Then I added a debug printk() to mv_write_main_irq_mask(), with no other changes, and that appears to > have been enough to change the race timing so that I could no longer produce the problem.
>
> Bruce, here's a slightly-ugly patch that should remove all doubt about races in the irq_mask.  Please > apply it, test with it, and let me know here if the issue goes away.
>
> Thanks

Thanks Mark. I was about to try out some tracing in writelfl because I
suspected the irq mask was getting clobbered somewhere along the way, but
I'd been distracted by other work.  I shall try your patch out as soon as
I can, and report back.

Cheers,

Bruce.


Bruce Stenning,
IndigoVision,
b <dot> stenning <at> indigovision <dot> com


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