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From: Mark Lord <liml@rtr.ca>
To: Tejun Heo <htejun@gmail.com>
Cc: Jeff Garzik <jgarzik@pobox.com>, linux-ide@vger.kernel.org
Subject: Re: [PATCH 2/2] libata: make sure IRQ is cleared after ata_bmdma_freeze()
Date: Thu, 16 Nov 2006 22:27:58 -0500	[thread overview]
Message-ID: <455D2C3E.8010509@rtr.ca> (raw)
In-Reply-To: <20061117030750.GE2184@htj.dyndns.org>

Tejun Heo wrote:
> 
> Note that ->freeze() handler is always called under ap->lock held and
> irq disabled.  Even if CTL manipulation causes stuck IRQ, it's cleared
> immediately.  This should be safe (enough) even in SMP environment.
> More correct solution is to mask the IRQ from IRQ controller but that
> would be an overkill.

Could this possibly lead to a "nobody cared" message from the IRQ layer,
followed by the kernel then disabling this IRQ?

Just wondering, because that's what can happen if we trigger an IRQ
but then don't report "handled" for it from our interrupt handler.

I'm puzzling through a similar situation in sata_qstor right now,
and the fix will involve manipulating the NIEN bit, with the same risk.

???

Thanks

  parent reply	other threads:[~2006-11-17  3:28 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-17  3:06 [PATCH 1/2] libata: move BMDMA host status recording from EH to interrupt handler Tejun Heo
2006-11-17  3:07 ` [PATCH 2/2] libata: make sure IRQ is cleared after ata_bmdma_freeze() Tejun Heo
2006-11-17  3:24   ` [PATCH 2/2 UPDATED] " Tejun Heo
2006-11-28  9:03     ` Jeff Garzik
2006-11-17  3:27   ` Mark Lord [this message]
2006-11-17  3:44     ` [PATCH 2/2] " Tejun Heo
2006-11-28  9:01 ` [PATCH 1/2] libata: move BMDMA host status recording from EH to interrupt handler Jeff Garzik

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