[PATCH] AMBA: Use suspend_noriq to force devices into runtime suspend
Ulf Hansson
ulf.hansson at stericsson.com
Tue Nov 1 05:32:22 EDT 2011
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
More information about the linux-arm-kernel
mailing list