From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: Hotplug drives on vt8251 with ahci module Date: Fri, 23 Jun 2006 20:42:14 +0900 Message-ID: <449BD396.8010209@gmail.com> References: <200606210942.33578.boac@wanadoo.nl> <44995139.30808@gmail.com> <200606220916.18020.boac@wanadoo.nl> <449A47EA.90601@gmail.com> <449A8A2A.2070102@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from wx-out-0102.google.com ([66.249.82.198]:53654 "EHLO wx-out-0102.google.com") by vger.kernel.org with ESMTP id S1750725AbWFWLmF (ORCPT ); Fri, 23 Jun 2006 07:42:05 -0400 Received: by wx-out-0102.google.com with SMTP id t5so18384wxc for ; Fri, 23 Jun 2006 04:42:05 -0700 (PDT) In-Reply-To: <449A8A2A.2070102@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: boac@wanadoo.nl, linux-ide@vger.kernel.org, Jeff Garzik [CC'ing Jeff. Hi!] Mark Lord wrote: > Tejun Heo wrote: >> >> About the disabling on hardreset failure... Maybe there is some room >> for improvement - e.g. leave PHY status interrupts alive if it's not >> causing interrupt storm, but I'm not sure whether the benefits would >> outweigh the cost. >> >> Leaving the port frozen (disabled & interrupts plugged) is a safety >> measure libata implements. The driver isn't sure in what state the >> controller and the attached device are in as they are not responding >> even to the 'hard' reset, so it assumes the worst and shuns the port. >> >> As I wrote above, you can ask libata to retry by explicitly telling >> libata to rescan the bus. I thought that should be enough when I was > > MMm.. sounds like libata should do that periodic polling, > rather than relying on the end-user to do it. Right? :) > > So the best of both approaches from above: mask the interrupts > and leave them off, but periodically poll for phy status changes. Hmm... Polling. Yeap, that's certainly a possibility. It's definitely better than selectively enabling PHY status change IRQ. Also, we can use the same facility to implement hotplug for ports which have SStatus but no PHY status changed IRQ. PMP requires command issuance for SStatus polling but PMP gets detached when a port gets frozen & disabled, so it doesn't matter anyway. I'll put this on my to-do list. Thanks for the suggestion. -- tejun