From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: PIO with SSDs: needs a long DRQ-after-command timeout for WRITEs Date: Wed, 31 Dec 2008 19:38:08 +0100 Message-ID: <200812311938.08916.bzolnier@gmail.com> References: <495A27E3.50801@rtr.ca> <20081230135902.560267dc@lxorguk.ukuu.org.uk> <495B9DDD.2020109@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-bw0-f21.google.com ([209.85.218.21]:47046 "EHLO mail-bw0-f21.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756199AbYLaSjU (ORCPT ); Wed, 31 Dec 2008 13:39:20 -0500 Received: by bwz14 with SMTP id 14so18734370bwz.13 for ; Wed, 31 Dec 2008 10:39:17 -0800 (PST) In-Reply-To: <495B9DDD.2020109@rtr.ca> Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: Alan Cox , Alan Cox , Tejun Heo , Jeff Garzik , IDE/ATA development list On Wednesday 31 December 2008, Mark Lord wrote: > Alan Cox wrote: > >> So.. how long does libata and current IDE allow for initial DRQ assertion? > >> It should probably be at least 500msec or more now. > > > > I think we need to rewrite the PIO code paths to use disable/enable_irq > > masking first before getting into adding long delays on PIO paths. > .. > > Yeah, that would be a good thing to do. Unless shared IRQs come into the picture -- in such case disabling IRQ for 0.5sec doesn't sound too sexy... > But in the meanwhile, a longer timeout there doesn't affect > any currently working systems -- they'll still wait only as long > as they currently do. And a longer timeout *will* enable these > SSDs to work where they otherwise would not. > > But perhaps the timeout is already long enough? > I don't know where the current timeout is hiding in libata. :) When it comes to IDE the timeout is defined by WAIT_DRQ in and is currently set to 100ms. There should be no problem with increasing it if it would help to get some devices to work (please just send a patch). Thanks, Bart