From: ulf.hansson@stericsson.com (Ulf Hansson)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] AMBA: Use suspend_noriq to force devices into runtime suspend
Date: Tue, 1 Nov 2011 10:32:22 +0100 [thread overview]
Message-ID: <4EAFBCA6.4020105@stericsson.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1110281051090.2175-100000@iolanthe.rowland.org>
Alan Stern wrote:
> On Fri, 28 Oct 2011, Ulf Hansson wrote:
>
>> The idea with having them as separate functions and something with
>> "runtime" in the name is because it is only when having
>> CONFIG_PM_RUNTIME the functions actually does something.
>
> No, that's off the main point.
>
> In fact, you're not really using these terms properly. You shouldn't
> think of "runtime suspend" as a single verb -- that is, you shouldn't
> think "Okay, let's runtime-suspend this device now".
>
> The verb is just "suspend", and it means the same thing as "put into a
> low-power state". The "runtime" part refers to _when_ the low-power
> transition takes place: while the rest of the system is running (as
> opposed to while the rest of the system is going to sleep).
>
> Thus, it makes no sense at all for a comment in a suspend_noirq
> callback to say "let's runtime-suspend the device". That's a
> contradiction in terms. The right way to think about it is more like
> this: "If the device isn't already in a low-power state, let's put it
> in a low-power state now".
>
> In your case, the device already is (or should be) at low power. A
> better way to phrase this might be: "If the device's power hasn't
> already been turned off, and the device doesn't need to generate wakeup
> requests, turn off the power now".
>
> Alan Stern
>
>
Ok, thanks for input! I will clarify my comments and commit message and
send a v3 patch (although the heading of the v3 patch will be changed to
not including something with "runtime" suspend).
BR
Ulf Hansson
prev parent reply other threads:[~2011-11-01 9:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-27 15:48 [PATCH] AMBA: Use suspend_noriq to force devices into runtime suspend Ulf Hansson
2011-10-27 15:54 ` Russell King - ARM Linux
2011-10-27 18:27 ` Linus Walleij
2011-10-27 19:48 ` Russell King - ARM Linux
2011-10-28 9:29 ` Ulf Hansson
2011-11-02 9:02 ` Russell King - ARM Linux
2011-11-02 10:55 ` Ulf Hansson
2011-11-02 12:51 ` Russell King - ARM Linux
2011-10-27 16:10 ` Alan Stern
2011-10-28 8:12 ` Ulf Hansson
2011-10-28 15:18 ` Alan Stern
2011-11-01 9:32 ` Ulf Hansson [this message]
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