From: Kevin Hilman <khilman@linaro.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linux PCI <linux-pci@vger.kernel.org>,
linux-usb@vger.kernel.org
Subject: Re: [RFC PATCH] PM / Runtime: Allow to inactivate devices during system suspend
Date: Tue, 19 Nov 2013 08:45:13 -0800 [thread overview]
Message-ID: <87r4acmjc6.fsf@linaro.org> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1311191011470.1145-100000@iolanthe.rowland.org> (Alan Stern's message of "Tue, 19 Nov 2013 10:35:46 -0500 (EST)")
Alan Stern <stern@rowland.harvard.edu> writes:
> On Tue, 19 Nov 2013, Ulf Hansson wrote:
>
>> At the moment, system PM is already affecting behaviour of runtime PM
>> since it is preventing runtime suspend during system suspend.
>
> Sure. And that behavior is documented. In any case, it's a bug for
> drivers to depend on runtime suspend for carrying out a system suspend.
As Rafael mentioned, there is bus/pm_domain code that comes into play
here, so I'm not sure it's always a bug.
IMO, it's not a bug for the driver to depend on runtime PM if the
bus/pm_domain is handling the details.
On OMAP, we handle all the SoC on-chip devices with a pm_domain since
the low-level PM operations that need to happen are bus-level things not
device-level things. Therefore, drivers for these devices can rely
entirely on runtime PM, even for system suspend. The late/early
callbacks in the pm_domain can see if the device is runtime suspended
already or not and behave accordingly.
So, this all *can* work by handling it at the bus/pm_domain level, but
as Ulf has mentioned (and I agree) it seems like a clunky workaround
because the PM core is preventing it from happening as one might expect.
Kevin
next prev parent reply other threads:[~2013-11-19 16:45 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-13 16:29 [RFC PATCH] PM / Runtime: Allow to inactivate devices during system suspend Ulf Hansson
2013-11-13 19:16 ` Alan Stern
2013-11-13 22:21 ` Rafael J. Wysocki
2013-11-14 13:21 ` Ulf Hansson
2013-11-14 15:59 ` Alan Stern
2013-11-14 16:40 ` Ulf Hansson
2013-11-14 17:57 ` Alan Stern
2013-11-15 8:44 ` Ulf Hansson
2013-11-15 9:29 ` Bjørn Mork
2013-11-15 10:34 ` Ulf Hansson
2013-11-15 15:22 ` Alan Stern
2013-11-18 13:27 ` Ulf Hansson
2013-11-18 15:17 ` Alan Stern
2013-11-19 12:21 ` Ulf Hansson
2013-11-19 13:21 ` Rafael J. Wysocki
2013-11-19 15:35 ` Alan Stern
2013-11-19 16:45 ` Kevin Hilman [this message]
[not found] ` <87r4acmjc6.fsf-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2013-11-19 18:03 ` Alan Stern
2013-11-19 18:43 ` Kevin Hilman
[not found] ` <Pine.LNX.4.44L0.1311191258550.1145-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org>
2013-11-21 9:00 ` Ulf Hansson
2013-11-21 15:54 ` Alan Stern
2013-11-22 8:19 ` Ulf Hansson
2013-11-22 12:06 ` Rafael J. Wysocki
2013-11-20 10:52 ` Ulf Hansson
2013-11-20 11:23 ` Pavel Machek
2013-11-20 11:53 ` Rafael J. Wysocki
2013-11-20 12:43 ` Ulf Hansson
2013-11-20 16:58 ` Alan Stern
2013-11-20 19:55 ` Pavel Machek
2013-11-20 16:55 ` Alan Stern
2013-11-13 22:13 ` Rafael J. Wysocki
[not found] ` <2003753.HAeVh74cdL-sKB8Sp2ER+y1GS7QM15AGw@public.gmane.org>
2013-11-14 14:32 ` Ulf Hansson
2013-11-14 15:55 ` Alan Stern
2013-11-21 9:11 ` Ulf Hansson
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