Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757523AbXI1Nlh (ORCPT ); Fri, 28 Sep 2007 09:41:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754409AbXI1Nl3 (ORCPT ); Fri, 28 Sep 2007 09:41:29 -0400 Received: from rtr.ca ([76.10.145.34]:3139 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754279AbXI1Nl1 (ORCPT ); Fri, 28 Sep 2007 09:41:27 -0400 Message-ID: <46FD0486.3060405@rtr.ca> Date: Fri, 28 Sep 2007 09:41:26 -0400 From: Mark Lord User-Agent: Thunderbird 2.0.0.6 (X11/20070728) MIME-Version: 1.0 To: Tejun Heo Cc: Alan Cox , Jeff Garzik , Andrew Morton , michal.k.k.piotrowski@gmail.com, bryan@arbores.ca, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org Subject: [PATCH] libata drain fifo on stuck DRQ HSM violation (try#2) References: <46CFA08E.6090604@arbores.ca> <6bffcb0e0708261610g10d9c59ck5789fac6feca9f42@mail.gmail.com> <46DBCB6C.8080206@gmail.com> <20070905095327.6277d054.akpm@linux-foundation.org> <46DEE617.4050004@rtr.ca> <46E0A253.7060803@gmail.com> <46E154DE.2060602@rtr.ca> <46FB563A.80108@gmail.com> <20070927193701.6230d77f@the-village.bc.nu> <46FC3D7D.90009@gmail.com> <46FC3FDD.5060201@pobox.com> <46FC423C.2050206@gmail.com> <46FC7B72.2030103@rtr.ca> <20070928112735.264733ad@the-village.bc.nu> In-Reply-To: <20070928112735.264733ad@the-village.bc.nu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3218 Lines: 97 Alan Cox wrote: >> Drain up to 512 words from host/bridge FIFO on stuck DRQ HSM violation, >> rather than just getting stuck there forever. > > Why 512 words ? > > >> ata_altstatus(ap); >> - ata_chk_status(ap); >> + ata_drain_fifo(ap, qc); > > ap->ops->cleanup(); > > might be wiser Actually, I belileve we should base it on qc->sect_size instead. Then, if somebody also would like to submit a patch introducing a cleanup() method, then please do so! As a separate patch, though (seems to be the "libata way"). * * * * Tejun Heo wrote: > Jeff Garzik wrote: >> Tejun Heo wrote: >>> Alan Cox wrote: >>>>> I think there have been enough cases where this draining was necessary. >>>>> IIRC, ata_piix was involved in those cases, right? If so, can you >>>>> please submit a patch which applies this only to affected controllers? >>>>> I don't feel too confident about applying this to all SFF controllers. >>>> Old IDE does it on all controllers bar a couple. So we have a very good >>>> knowledge of what does/doesn't work. The one that needs care in old ide >>>> is an ordering issue where a state machine reset done first causes the >>>> drain of the I/O to hang. >>> Hmmm... So, do we apply draining to all PATA? Or is ata_piix SATA >>> affected too? >> I would think all SFF controllers, since a lot of first gen SATA are >> really bridged solutions. If they are flagging DRQ, I say oblige them :) > > Alright, then the posted patch should be good enough. Mark, can you be > bothered to regenerate the patch and post it one more time (again)? It > seems we all agree the update is needed. I think this original patch still applies cleanly on at least 2.6.23-rc7. Drain up to 512 words from host/bridge FIFO on stuck DRQ HSM violation, rather than just getting stuck there forever. Signed-off-by: Mark Lord --- --- old/drivers/ata/libata-sff.c 2007-09-28 09:29:22.000000000 -0400 +++ linux/drivers/ata/libata-sff.c 2007-09-28 09:39:44.000000000 -0400 @@ -420,6 +420,28 @@ ap->ops->irq_on(ap); } +static void ata_drain_fifo(struct ata_port *ap, struct ata_queued_cmd *qc) +{ + u8 stat = ata_chk_status(ap); + /* + * Try to clear stuck DRQ if necessary, + * by reading/discarding up to two sectors worth of data. + */ + if ((stat & ATA_DRQ) && (!qc || qc->dma_dir != DMA_TO_DEVICE)) { + unsigned int i; + unsigned int limit = qc ? qc->sect_size : ATA_SECT_SIZE; + + printk(KERN_WARNING "Draining up to %u words from data FIFO.\n", + limit); + for (i = 0; i < limit ; ++i) { + ioread16(ap->ioaddr.data_addr); + if (!(ata_chk_status(ap) & ATA_DRQ)) + break; + } + printk(KERN_WARNING "Drained %u/%u words.\n", i, limit); + } +} + /** * ata_bmdma_drive_eh - Perform EH with given methods for BMDMA controller * @ap: port to handle error for @@ -476,7 +498,7 @@ } ata_altstatus(ap); - ata_chk_status(ap); + ata_drain_fifo(ap, qc); ap->ops->irq_clear(ap); spin_unlock_irqrestore(ap->lock, flags); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/