From: Tejun Heo <tj@kernel.org>
To: Lin Ming <ming.m.lin@intel.com>
Cc: Jeff Garzik <jgarzik@pobox.com>,
Alan Stern <stern@rowland.harvard.edu>,
linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org,
linux-pm@vger.kernel.org, "Rafael J. Wysocki" <rjw@sisk.pl>,
kay.sievers@vrfy.org
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 [thread overview]
Message-ID: <20111215192131.GE32002@google.com> (raw)
In-Reply-To: <1323954769-3918-5-git-send-email-ming.m.lin@intel.com>
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
next prev parent reply other threads:[~2011-12-15 19:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-15 13:12 [RFC][PATCH 0/4] ahci controller runtime PM support Lin Ming
2011-12-15 13:12 ` [RFC][PATCH 1/4] ahci: port legacy pm interface to struct dev_pm_ops Lin Ming
2011-12-15 19:53 ` Rafael J. Wysocki
2011-12-16 13:07 ` Lin Ming
2011-12-15 13:12 ` [RFC][PATCH 2/4] ahci: add runtime PM callbacks Lin Ming
2011-12-15 13:12 ` [RFC][PATCH 3/4] ata: runtime suspend port if no device attached Lin Ming
2011-12-15 13:12 ` [RFC][PATCH 4/4] ahci: support hot plug when port/controller is runtime suspended Lin Ming
2011-12-15 19:21 ` Tejun Heo [this message]
2011-12-15 23:29 ` Kay Sievers
2012-01-02 15:57 ` Matthew Garrett
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