Messages in this thread | | | From | Ulf Hansson <> | Date | Thu, 9 Sep 2021 16:45:38 +0200 | Subject | Re: [PATCH 1/3] PM: domains: Drop the performance state vote for a device at detach |
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On Thu, 9 Sept 2021 at 15:48, Dmitry Osipenko <digetx@gmail.com> wrote: > > 07.09.2021 13:16, Ulf Hansson пишет: > ... > >>> Also note that a very similar problem exists, *before* the device gets > >>> attached in the first place. More precisely, nothing prevents the > >>> performance state from being set to a non-compatible value for an > >>> always-on HW/device that hasn't been attached yet. So maybe you need > >>> to set the maximum performance state at genpd initializations, then > >>> use the ->sync_state() callback to very that all consumers have been > >>> attached to the genpd provider, before allowing the state to be > >>> changed/lowered? > >> > >> That is already done by the PD driver. > >> > >> https://elixir.bootlin.com/linux/latest/source/drivers/soc/tegra/pmc.c#L3790 > > > > Yes, I already knew that, but forgot it. :-) Thanks for the pointer. > > Let me rethink the approach. > > > > In a way, it kind of sounds like this is a generic problem - so > > perhaps we should think of adding a ->withdraw_sync_state() callback > > that can be assigned by provider drivers, to get informed when a > > consumer driver is getting unbinded. > > Not sure, doesn't feel to me that this is necessary for today. A bit too > cumbersome for a simple sanity-check, IMO.
Maybe, but I can bring it up with the fw_devlinks people to see what they think.
In any case, we should not move forward with $subject patch as is.
Let me think about it.
Kind regards Uffe
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