From: Pascal GREGIS <pgs@synerway.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: ata_sff_drain_fifo
Date: Wed, 18 Aug 2010 18:23:29 +0200 [thread overview]
Message-ID: <20100818162329.GC3029@gaiman.synerway.com> (raw)
In-Reply-To: <20100818124412.4652eaea@lxorguk.ukuu.org.uk>
Alan Cox a écrit, le mer 18 aoû 2010 à 12:44:12 :
> > so I guess when status is 0xD0, ATA_DRQ is not set but ATA_BUSY is.
> > It would explain why in my case it doesn't drain anything before trying to reset.
> >
> > Would it be of any interest to drain the fifo also when the ATA_BUSY flag is on, not only the ATA_DRQ ?
>
> If the drive has the busy flag set it is busy, all we can do is wait for
> it and if that fails try to reset it. The FIFO drain handles a specific
> case where the two ends disagree about the amount of data expected, and
> often lets us avoid a reset.
Ok. I also noticed that qc->dma_dir=DMA_TO_DEVICE which also prevents the draining.
I thought it could be a solution for certain problems like mine where the device is busy but the reset doesn't work which brings to a blocking point, but no.
Pascal
>
> Alan
next prev parent reply other threads:[~2010-08-18 16:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-18 9:43 ata_sff_drain_fifo Pascal GREGIS
2010-08-18 11:44 ` ata_sff_drain_fifo Alan Cox
2010-08-18 16:23 ` Pascal GREGIS [this message]
2010-08-18 17:31 ` ata_sff_drain_fifo Alan Cox
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