From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [RFC PATCH] libata-sff: Fix oops reported in kerneloops.org for pnp devices with no ctl Date: Thu, 29 May 2008 17:57:04 -0400 Message-ID: <483F26B0.8010006@garzik.org> References: <20080529161453.24735.805.stgit@core> <20080529190235.258d304e@core> <483EF536.90801@garzik.org> <20080529194238.36458a46@core> <483F049E.2090809@garzik.org> <20080529221058.1169e140@core> <20080529223755.12610b87@core> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:54690 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752599AbYE2V5G (ORCPT ); Thu, 29 May 2008 17:57:06 -0400 In-Reply-To: <20080529223755.12610b87@core> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org Alan Cox wrote: > The Linusified version: > > - Make ata_sff_altstatus private so nobody uses it by mistake > - Drop the 400nS delay from it > > Add > > ata_sff_irq_status - encapsulates the IRQ check logic > > This function keeps the existing behaviour for altstatus using devices. I > actually suspect the logic was wrong before the changes but -rc isn't the > time to play with that > > ata_sff_sync - ensure writes hit the device > > Really we want an io* operation for 'is posted' eg ioisposted(ioaddr) so > that we can fix the nasty delay this causes on most systems. > > - ata_sff_pause - 400nS delay > > Ensure the command hit the device and delay 400nS > > - ata_sff_dma_pause > > Ensure the I/O hit the device and enforce an HDMA1:0 transition delay. > Requires altstatus register exists, BUG if not so we don't risk > corruption in MWDMA modes. (UDMA the checksum will save your backside in > theory) > > The only other complication then is devices with their own handlers. > rb532 can use dma_pause but scc needs to access its own altstatus > register for internal errata workarounds so directly call the drivers own > altstatus function. > > Signed-off-by: Alan Cox Honestly I think your first RFC PATCH (dated Thu, 29 May 2008 22:10:58 +0100) turned out better than this. NO_ALTSTATUS is a bit ugly, don't you think? In any case, based on a quick review I would certainly ack the first RFC PATCH. Jeff