Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268255AbTGINgG (ORCPT ); Wed, 9 Jul 2003 09:36:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268256AbTGINgG (ORCPT ); Wed, 9 Jul 2003 09:36:06 -0400 Received: from CPE00e02915899a-CM.cpe.net.cable.rogers.com ([24.157.227.104]:45442 "EHLO mokona.furryterror.org") by vger.kernel.org with ESMTP id S268255AbTGINgD (ORCPT ); Wed, 9 Jul 2003 09:36:03 -0400 From: Zygo Blaxell Subject: Re: 2.4.21 IDE and IEEE1394+SBP2 regressions, orinoco_pci progress Date: Wed, 09 Jul 2003 09:50:40 -0400 Organization: Furry Cats and Hungry Terrors Message-ID: References: <3F0B8844.9070108@c-zone.net> User-Agent: Pan/0.11.2 (Unix) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Comment-To: "jiho" NNTP-Posting-Host: 10.215.3.77 X-Header-Mangling: Original "From:" was To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2127 Lines: 42 On Tue, 08 Jul 2003 23:13:08 -0400, jiho wrote: > Zygo Blaxell wrote: > Excuse my ignorance -- I suppose I'm blundering around here with a > number of IDE issues -- but what do you mean by, "at suspend time"? At the time I either hit the appropriate key sequence on the laptop, or run the 'apm -s' command, or when battery power drops below an arbitrary threshold, which causes the laptop to go into a low power mode (memory is powered, but CPU is stopped and all non-memory-related hardware is turned off). > How can there be a "suspend time" while a disk I/O request is "in > progress"? For this to happen there has to be a process or processes doing a lot of disk I/O at the moment that the suspend event occurs (which is typical if e.g. compiling a kernel while on battery power, and the battery power runs out half way through). I'm guessing here, but I suspect that at least one IDE request has been sent to the drive, but a reply has not been received yet, when the APM BIOS stops executing Linux and cuts power to the drive. When the laptop resumes some time later, the APM BIOS turns the drive back on and resumes executing Linux. AFAICT APM expects the OS to take care of re-issuing the last command to the IDE disk, or expects the OS to avoid issuing a command just before the OS tells APM that it's ready to suspend. Either approach would work. Linux is still waiting for this command to complete after it resumes, but of course the drive and controller hardware don't remember what the command was as they've been turned off in the meantime. In 2.4.20 and earlier, the kernel would wait a few seconds, then reset the IDE hardware and try the command again. In 2.4.21, the kernel locks up hard. Judging from my boolean CPU meter (aka the laptop fan, which activates during periods of high CPU activity), the CPU isn't very busy when it is locked up like this. - 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/