From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: SATA_SIL on IXP425 workaround Date: Thu, 21 Jan 2010 00:00:02 -0500 Message-ID: <4B57DF52.2030906@garzik.org> References: <201001141659.19687.bzolnier@gmail.com> <20100114192210.62593ead@lxorguk.ukuu.org.uk> <201001142129.38781.bzolnier@gmail.com> <20100114210050.2c99c2b1@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100114210050.2c99c2b1@lxorguk.ukuu.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: Alan Cox Cc: Bartlomiej Zolnierkiewicz , Krzysztof Halasa , linux-ide@vger.kernel.org, lkml List-Id: linux-ide@vger.kernel.org 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. Jeff