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From: Alan Cox <>
Cc: Guennadi Liakhovetski <>,
	Tim Ellis <>,,
Subject: Re: [PATCH] libata: Add MMIO support to pata_sil680
Date: Fri, 15 Feb 2008 22:27:25 +0000	[thread overview]
Message-ID: <20080215222725.0af29563@core> (raw)
In-Reply-To: <1203111956.22915.24.camel@pasglop>

> The dbdma start is mostly harmless (things don't get posted for -that-
> long), though I suppose it's worth fixing. Would reading back dmactl do
> in that case or do you foresee any kind of side effect ? (Maybe only
> doing it for MMIO ?)

The dmactl read back should be just fine, or any other DMA register (eg

> As for SRST, I'm not totally confident how safe it is to read back
> there while doing the reset sequence, so I'm tempted to really only
> do it for MMIO and use altstat rather than ctl/stat (the later tends
> to have side effects which we don't want here).

Agreed - we know some controllers crap themselves spectacularly on
anything which causes a SATA data transfer to be needed during a reset so
the status is probably safest. The fact its not fixed is because nobody
has sat down to figure out what is safe.

> The main problem from here is that I don't know whether we are using
> MMIO or PIO from libata-core. Maybe I can add a host flag indicate
> that such flushing is needed ?

Easier to add that to the ioxxxx ops I suspect (ioispio/ioismmio say) ?


  reply	other threads:[~2008-02-15 22:36 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-12 15:58 Tim Ellis
2008-02-12 21:02 ` Benjamin Herrenschmidt
2008-02-12 21:42   ` Alan Cox
2008-02-15 15:52   ` Guennadi Liakhovetski
2008-02-15 15:53     ` Alan Cox
2008-02-15 21:45       ` Benjamin Herrenschmidt
2008-02-15 22:27         ` Alan Cox [this message]
2008-02-15 22:55           ` Benjamin Herrenschmidt
2008-02-15 23:56         ` Tim Ellis
2008-02-25 22:57           ` Jeff Garzik
2008-02-25 23:06             ` Guennadi Liakhovetski
2008-02-26  0:58             ` Benjamin Herrenschmidt
2008-03-25 23:31               ` [PATCH] Work around breakage introduced in pata_sil680 by switching it to MMIO Guennadi Liakhovetski
2008-03-25 23:36                 ` Alan Cox
2008-03-26  8:20                   ` Benjamin Herrenschmidt
2008-02-15 21:36     ` [PATCH] libata: Add MMIO support to pata_sil680 Benjamin Herrenschmidt

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