From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [RFC][PATCH 4/4] ahci: support hot plug when port/controller is runtime suspended Date: Thu, 15 Dec 2011 11:21:31 -0800 Message-ID: <20111215192131.GE32002@google.com> References: <1323954769-3918-1-git-send-email-ming.m.lin@intel.com> <1323954769-3918-5-git-send-email-ming.m.lin@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-iy0-f174.google.com ([209.85.210.174]:34185 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759366Ab1LOTVh (ORCPT ); Thu, 15 Dec 2011 14:21:37 -0500 Content-Disposition: inline In-Reply-To: <1323954769-3918-5-git-send-email-ming.m.lin@intel.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Lin Ming Cc: Jeff Garzik , Alan Stern , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-pm@vger.kernel.org, "Rafael J. Wysocki" , kay.sievers@vrfy.org Hello, On Thu, Dec 15, 2011 at 09:12:49PM +0800, Lin Ming wrote: > I use eSATA to test disk hot plug. > With previous 3 patches applied, disk hot plug does not wok > when ahci port/controller is runtime suspended. > > There are 2 cases we need to handle for hot plug: > > 1. port suspended, controller active > Is IRQ need to be enabled for port to detect hot plug? > > 2. port suspended, controller suspended > Will controller get a PME when hot plug happens? > > I'm still investigating hot plug support. > > Anyone has comment? SATA link detection requires hot wire and keeping wire hot takes power. I think it's fair tradeoff to not support hotplug while powersaving is on. We have warm plug mechanism (the SCSI rescan trigger via sysfs) after all. It would be nice if things like that is somehow exported to userland in easy way tho (cc'ing Kay), but I frankly don't have much idea where that would fit. Thanks. -- tejun