Re: [PATCH] radeon: Make PM info available to all, not just debug users

[Martin Peres <martin.peres@free.fr>]

Le 04/06/2012 16:31, Jerome Glisse a écrit :
>
> I don't think sysfs is the way to go, i am pretty sure that power
> management will change drasticly again in the future especialy btw
> discret and integrated GPU. I would rather have hardware specific
> ioctl.
>
> Cheers,
> Jerome
Any particular idea of what may change?

The proposed interface would work even on entirely dynamic
reclocking (per-domain frequency scaling) as opposed to
perflvl-based reclocking. It is unlikely to happen though.

A more realistic possibility could be that engines would be reclocked
independently according to their internal load.
If that was to happen, then the already-existing API could be used as
a master control and engines could specify the performance level policy
they want (follow master, always min, always max, conservative, dynamic).

I'm pretty sure voltage domains will soon appear but I don't see what could
possibly be changed that wouldn't be covered by what I proposed.

As for the reason we would like to use IOCTLs instead of sysfs, I really
don't understand what is the rationale. I personally want to empower the
users to let them decide what is best for them. Sysfs is way easier to
work with!

Although my idea may be sketchy, I am dead-serious about coming up with
a good API.

Martin