From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH] updated version of Jens' SATA suspend-to-ram patch Date: Sat, 24 Sep 2005 09:07:04 +0200 Message-ID: <20050924070659.GK22655@suse.de> References: <20050923163334.GA13567@triplehelix.org> <20050923180711.GH22655@suse.de> <433469DF.1060900@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from ns.virtualhost.dk ([195.184.98.160]:4947 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S1751452AbVIXHHD (ORCPT ); Sat, 24 Sep 2005 03:07:03 -0400 Content-Disposition: inline In-Reply-To: <433469DF.1060900@pobox.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jeff Garzik Cc: torvalds@osdl.org, joshk@triplehelix.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org On Fri, Sep 23 2005, Jeff Garzik wrote: > >--- linux-2.6.13/drivers/scsi/libata-core.c~ 2005-09-01 > >12:22:19.000000000 +0200 > >+++ linux-2.6.13/drivers/scsi/libata-core.c 2005-09-01 > >12:24:38.000000000 +0200 > >@@ -3738,8 +3738,8 @@ > > unsigned long flags; > > int rc; > > > >- qc = ata_qc_new_init(ap, dev); > >- BUG_ON(qc == NULL); > >+ while ((qc = ata_qc_new_init(ap, dev)) == NULL) > >+ msleep(10); > > > > qc->tf.command = cmd; > > qc->tf.flags |= ATA_TFLAG_DEVICE; > > Worried now! > > If this patch is needed, something VERY VERY WRONG is going on. This > patch indicates that the queueing state machine has been violated, and > something is trying to IGNORE the command synchronization :( I haven't diagnosed this further and it only ever happened in the SUSE kernel to my knowledge (no one has reported it to me for the vanilla kernels + suspend patch). So lets just keep this patch out of the equation for now, it could be that other SUSE patches broke something in this area :/ > Further, you cannot always assume that msleep() is valid in that > context. It should be the caller that waits (libata suspend code), not > ata_do_simple_cmd() itself. ata_do_simple_cmd() always blocks anyways, so I don't see the point. Perhaps rename the function to ata_execute_and_wait_simple_cmd(). -- Jens Axboe