From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752955AbXKXFTz (ORCPT ); Sat, 24 Nov 2007 00:19:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751607AbXKXFTp (ORCPT ); Sat, 24 Nov 2007 00:19:45 -0500 Received: from rv-out-0910.google.com ([209.85.198.185]:44519 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751140AbXKXFTo (ORCPT ); Sat, 24 Nov 2007 00:19:44 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:x-enigmail-version:content-type:content-transfer-encoding; b=e/QSxsumDSEHW7FNdglXsTpJKPxIjFXDun7CbMPcqq5Sb1GQoG0ubpqW1FwAiB9CTqI/vfv0KmJ+g9/cYAqiS0mQl0dOdONjFw5oKSWyw3s42u0QqMSnibYp0YYBUYmtWf//xB5mwM3mSQpyopxEu7l0WMO3Mm2fKZv7WAm5OQA= Message-ID: <4747B46A.5000503@gmail.com> Date: Sat, 24 Nov 2007 14:19:38 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.6 (X11/20070801) MIME-Version: 1.0 To: Robert Hancock CC: linux-kernel , ide , Jeff Garzik Subject: Re: [PATCH] sata_nv: don't use legacy DMA in ADMA mode (v2) References: <47463580.8080909@shaw.ca> <4747B3BB.4000708@gmail.com> In-Reply-To: <4747B3BB.4000708@gmail.com> X-Enigmail-Version: 0.95.3 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Tejun Heo wrote: > Robert Hancock wrote: >> We need to run any DMA command with result taskfile requested in ADMA mode >> when the port is in ADMA mode, otherwise it may try to use the legacy DMA engine >> in ADMA mode which is not allowed. Enforce this with BUG_ON() since data >> corruption could potentially result if this happened. Also WARN_ON() if we try >> and send result taskfile commands while NCQ commands are still active, since the >> hardware doesn't allow this. >> >> Signed-off-by: Robert Hancock >> >> @@ -1425,9 +1427,17 @@ >> + /* We can't handle result taskfile with NCQ commands active, since >> + retrieving the taskfile switches us out of ADMA mode and would abort >> + existing commands. */ >> + WARN_ON((qc->flags & ATA_QCFLAG_RESULT_TF) && >> + (qc->ap->qc_allocated & ~(1 << qc->tag))); > > I owe an apology here. ap->qc_allocated & ~(1 << qc->tag) test isn't > correct. Sorry. qc deferring happens after qc is allocated so the > condition can trigger (although it should be rare) even when nothing is > going wrong, so I guess it should be WARN_ON((qc->flags & > ATA_QCFLAG_RESULT_TF) && link->sactive). Or, just make the assumption clear by not allowing NCQ w/ RESULT_TF at all. if (unlikely(qc->tf.protocol == ATA_PROT_NCQ && (qc->flags & ATA_QCFLAG_RESULT_TF)) { ata_dev_printk(qc->dev, KERN_ERR, "NCQ w/ RESULT_TF not allowed\n"); return AC_ERR_SYSTEM; } Thanks. -- tejun