[Intel-gfx] [PATCH 0/5] PowerManagement Toggle for PowerTOP

[Daniel Vetter]

On Fri, Apr 15, 2016 at 06:12:32PM +0000, Vivi, Rodrigo wrote:
> I was talking to PM engineers today on their Summit and they are really
> interrested in a way to toggle features on/off easily.
> 
> They also told if debugfs is the only way that powertop should have to
> deal with it.
> 
> So I see two ways here:
> 
> 1. Stable informative only sysfs interface with powertop always
> displaying it. No toggles
> 
> 2. Stable informative only sysfs interface with powertop always displaying it. Toggle on debugfs only not implemented on powertop.
> 
> 3. Powertop showing status via debugfs, but not toggling it. Plus Toggle on debugfs only not implemented on powertop.
> 
> 4. Powertop informative and toggle using debugfs. Probably forcing
> powertop to create a flag --debug-only with a warning that it is
> unsafe.
> 
> What do you think: 1, or 2, or 3, or 4, or none?

I still don't get the use-case for toggling random power features. What
are people trying to accomplish with that? All the scenarios I can come up
with are imo well-served with the current module options we have.

Now maybe we should document how to best debug power issues better, but
imo what's really needed for that is proper residency counters. And
automatically displaying what exactly is blocking a deeper sleep state.
Both things only the magic PM firmware knows, and currently doesn't tell
us :(
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch