On 10 October 2013 16:45, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 10 Oct 2013, Ulf Hansson wrote:
>
>> Typically the runtime idle function is triggered after resume and
>> probe. Instead of immediately requesting the device to go into
>> in-active state we make use of the autosuspend, if we have enabled
>> it earlier.
>>
>> Cc: Len Brown <len.brown@xxxxxxxxx>
>> Cc: Pavel Machek <pavel@xxxxxx>
>> Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
>> Cc: Kevin Hilman <khilman@xxxxxxxxxx>
>> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
>> Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
>> Cc: linux-pm@xxxxxxxxxxxxxxx
>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>> ---
>> drivers/mmc/core/bus.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
>> index cdca8a7..7f0e900 100644
>> --- a/drivers/mmc/core/bus.c
>> +++ b/drivers/mmc/core/bus.c
>> @@ -205,6 +205,12 @@ static int mmc_runtime_resume(struct device *dev)
>>
>> static int mmc_runtime_idle(struct device *dev)
>> {
>> + if (pm_runtime_autosuspend_used(dev)) {
>> + pm_runtime_mark_last_busy(dev);
>> + pm_runtime_autosuspend(dev);
>> + return -EBUSY;
>> + }
>> +
>> return 0;
>> }
>
Hi Alan,
Thanks for response!
> I would greatly prefer to see the core rpm_idle() routine changed
> instead. Currently the last line says:
>
> return retval ? retval : rpm_suspend(dev, rpmflags);
>
> The second argument to rpm_suspend should be rpmflags | RPM_AUTO. That
> way, if the runtime-idle callback returns 0, we will automatically do
> either a normal suspend or an autosuspend, whichever is appropriate.
I know you guys, Mika and Rafael had a discussion around this feature
a few month ago. Were thinking of you sending this response. :-)
At that time, Rafael suggested to go ahead using similar method as I
implemented here, which is also what Mika proposed for
drivers/i2c/busses/i2c-designware-platdrv.c, not sure he finally sent
a formal patch though.
Anyway, just wanted us all to be aligned on the best way forward. I am
also in favour of fixing this in the runtime PM core. How do you
think we shall handle drivers that not have the runtime_idle
callbacks? I guess we want to use the RPM_AUTO flag here as well?
>
> As an added benefit, with this change there's no need to add the
> pm_runtime_autosuspend_used() function.
In my patch I am also checking if I should update the last busy mark,
do you mean it should be okay to do this even if not needed?
>
> Alan Stern
>
Kind regards
Ulf Hansson
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