Re: SATA_SIL on IXP425 workaround

From: Jeff Garzik
Date: Thu Jan 21 2010 - 00:00:21 EST

On 01/14/2010 04:00 PM, Alan Cox wrote:
I think that you misinterpreted the issue -- according to Krzysztof MMIO
works just fine, only 8/16-bit MMIO reads are a problem (please note that
using mixed PIO/MMIO access is still a win over pure PIO access and also
that sata_sil doesn't support pure non-MMIO operations currently)..

Have we got timing measurements to prove that ?

However if it gets fixed in the upstream kernel in some other way I'll
simply drop the patch during the next re-base of my tree (I just collect
ATA stuff that looks useful/interesting to me and which otherwise may
become lost)..

And that's a good thing. The question was aimed at Krzysztof. Really we
need to keep platform specific weirdness out of core drivers or the
rapidly turn into a mess.

The lack of 8-/16-byte MMIO access is unfortunately not limited to Krzysztof's platform. Other people have reported the same problem specifically with sata_sil (see the archives).

If the driver cannot be converted to all-32-bit accesses, we will need to do something like Krzysztof's patch.


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