Re: [PATCH 1/11] ARM: tegra: add function to control the GPU rail clamp

[Vince Hsu]

On 01/07/2015 10:48 PM, Thierry Reding wrote:
> * PGP Signed by an unknown key
>
> On Wed, Jan 07, 2015 at 10:28:29PM +0800, Vince Hsu wrote:
> > On 04:08:52PM Jan 07, Peter De Schrijver wrote:
> > > On Wed, Jan 07, 2015 at 02:27:10PM +0100, Thierry Reding wrote:
> > >
> > > > > Yeah. I plan to have the information of all the clock client of the
> > > > > partitions and
> > > > > the memory clients be defined statically in c source, e.g. pmc-tegra124.c.
> > > > > All modules can declare which domain they belong to in DT. One domain can
> > > > > be really power gated only when no module is awake. Note the clock clients
> > > > > of
> > > > > one domain might not equal to the clocks of the module. The reset is not
> > > > > either.
> > > > > So I don't get the clock and reset from module. How do you think?
> > > > This whole situation is quite messy. The above sequence basically means
> > > > that drivers can't reset hardware modules because otherwise they might
> > > > race with the power domain code. It also means that we can't powergate
> > > The powerdomain framework won't call any powergating method as long as a
> > > module in the domain is still active. So as long as drivers don't try to
> > > reset the hw without having done a pm_runtime_get(), we shouldn't have such
> > > a race?
> > Agree. And as long as the driver has the correct reset procedure, that should
> > be fine to occur between power ungating and gating sequences.
> >
> > > > modules on demand because they might be in the same power domain as one
> > > > other module that's still busy.
> > > The powerdomain framework keeps track of which modules are active (by hooking
> > > into runtime pm) and won't try to shutdown a domain unless all modules are
> > > inactive.
> > Yeah. By the way, that means we should start supporting runtime pm for all
> > the modules to use generic power domain.
> Indeed, that'll be a prerequisite before we can merge power domain
> support. I do have a couple of local patches that add very rudimentary
> runtime PM for various drivers. For starters we could probably just do
> the
>
> 	pm_runtime_enable(...);
> 	pm_runtime_get_sync(...)
>
> in the ->probe() and
>
> 	pm_runtime_put_sync(...);
> 	pm_runtime_disable(...);
>
> in the ->remove() callbacks for those drivers. That's by no means
> optimal but should get us pretty close to what we do now and still
> support the generic power domains.
Cool. Could you send me the patches?

Thanks,
Vince

> Thierry
>
> * Unknown Key
> * 0x7F3EB3A1

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