From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH 2.6.25-rc6] sata_promise: fix hardreset hotplug events, take 2 Date: Mon, 24 Mar 2008 22:31:55 -0400 Message-ID: <47E8641B.3030309@garzik.org> References: <200803221421.m2MEL1oY021558@harpo.it.uu.se> <18406.38445.717175.664615@harpo.it.uu.se> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:56431 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757216AbYCYCb7 (ORCPT ); Mon, 24 Mar 2008 22:31:59 -0400 In-Reply-To: <18406.38445.717175.664615@harpo.it.uu.se> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mikael Pettersson Cc: htejun@gmail.com, kurt@roeckx.be, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Mikael Pettersson wrote: > A Promise SATA controller will signal hotplug events when a hard > reset (COMRESET) is done on a port. These events aren't masked by > the driver, and the unexpected interrupts will cause a sequence > of failed reset attempts util libata's EH finally gives up. > > This has not been a common problem so far, but the pending libata > hardreset-by-default changes makes it a critical issue. > > The solution is to disable hotplug events before a reset, and to > reenable them afterwards. (Promise's driver does this too.) > > This patch adds SATA-specific versions of ->freeze() and ->thaw() > that also disable and enable hotplug events. PATA ports continue > to use the old versions of ->freeze() and ->thaw(). > > Accesses to the hotplug register must be serialised via host->lock. > We rely on ap->lock == &ap->host->lock and that libata takes this > lock before ->freeze() and ->thaw(). Document this requirement. > The interrupt handler is adjusted so its hotplug register accesses > are inside the region protected by host->lock. > > Tested on various chips (SATA300TX4, SATA300TX2plus, SATAII150TX4, > FastTrack TX4000) with various combinations of SATA and PATA disks, > with and without the pending hardreset-by-default changes. > > Signed-off-by: Mikael Pettersson > --- > Changes since previous version: > - rephrase the problem description to avoid calling it a HW quirk, > the behaviour is apparently standard > - fix double locking bug found by Tejun, now tested with SMP kernel > - document locking rules for the global hotplug register > - inline the hotplug enable/disable code in freeze/thaw > > drivers/ata/sata_promise.c | 109 ++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 88 insertions(+), 21 deletions(-) applied