[Intel-gfx] [PATCH] drm/i915: decouple runtime PM enablement from DMC presence

[Stéphane Marchesin]

On Mon, Jun 19, 2017 at 11:45 AM, Jani Nikula
<jani.nikula at linux.intel.com> wrote:
>
> On Thu, 15 Jun 2017, Imre Deak <imre.deak at intel.com> wrote:
> > On Thu, Jun 15, 2017 at 10:20:57AM -0700, Rodrigo Vivi wrote:
> >> I believe it is worth allowing RPM to work without requiring DMC, no?!
> >
> > Not if there is no good reason for not using DMC. It was decided early
> > on that we won't support that configuration since if you care about the
> > power saving provided by partially disabling things you probably also
> > care about the bigger power saving provided by DMC. So that is the
> > current state of the driver, enabling runtime PM without having DMC
> > loaded is not supported. Proper support for that would need to be added
> > after a justification why not to use the firmware.
>
> Agreed. We already have too many configurations to support, and we
> already struggle with our testing coverage as-is. Adding new
> configurations to be tested is not to be taken lightly.
>

For context, we are seeing GPU hangs at suspend/resume with DMC
enabled (feel free to email me if you want to be added to the internal
bug) which is the reason for this patch. If those GPU hangs can be
fixed instead, then that would be an even better solution, IMO. Is
there someone on your side who could help with these hangs?

Stéphane

>
> BR,
> Jani.
>
> --
> Jani Nikula, Intel Open Source Technology Center