Messages in this thread | | | Date | Mon, 5 Sep 2022 15:54:54 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH 0/2] opp: core: add regulators enable and disable |
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On 05-09-22, 10:28, Clément Péron wrote: > Hi Viresh, > > On Mon, 5 Sept 2022 at 06:35, Viresh Kumar <viresh.kumar@linaro.org> wrote: > > > > On 03-09-22, 22:35, Clément Péron wrote: > > > Today, I compiled my kernel without any program requiring GPU > > > computing at boot.
I thought you disabled most of GPU stuff here and so thought panfrost devfreq will be gone too :)
> > > This makes the dev_pm_opp_set_rate() to never be > > > called and so the regulator is not enabled before the regulator > > > framework switches off all the regulators that haven't been enabled. > > > > > > Unfortunately switching off the GPU regulator makes my board hang.. > > > > Why does the board hang? I mean the kernel should boot fine with the > > GPU disabled, isn't it ? Or is the regulator shared with some other > > critical resource, or something else. > > The regulator is dedicated to the GPU and the board could certainly > run without GPU, the issue is that the driver (here panfrost) may do > some regular access to GPU memory (I suppose).
So we do need GPU to be functional at this point ? i.e. both clk/regulators should be enabled.
> The code I'm pointing is panfrost_devfreq_init() in > drivers/gpu/drm/panfrost/panfrost_devfreq.c
I think it would be better to call dev_pm_opp_set_opp() after calling devfreq_recommended_opp() in this driver, since you already have the OPP known to you.
-- viresh
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