[alsa-devel] [PATCH v2 2/3] ASoC: SOF: acpi: add module param to disable pm_runtime

[Pierre-Louis Bossart]

>>> I can't immediately find it right now but isn't there some generic way
>>> of doing this in the runtime PM framework?  If not it seems like it'd be
>>> a good thing to add, these can't be the only devices where it'd be
>>> useful.
> 
>> Well, runtime PM can be fully controlled via sysfs, but the problem is
>> that the driver declares itself being runtime-enabled.
>> So, either we leave it default and let user-space enabling it (via
>> udev or other way), or introduce some condition in the driver side.
> 
> I thought someone had added a command line parameter to do it based on
> dev_name(), perhaps they were just talking about it or it was in some
> BSP somewhere though.

If there is a better way I am all ears. It's indeed not very elegant to 
duplicate the same parameter for two different modules and it's not an 
SOF-specific need.

The only way I am aware of is to play with 
/sys/bus/pci/devices/xyz/power/ files but it's not very useful if you 
want to disable the initial runtime pm transition which is often the 
more problematic one. Completely removing runtime_pm support from all 
drivers at compile time is also not very good either.