Re: [PATCH v2 1/2] clk: tegra: Mark HCLK, SCLK, EMC, MC and PLL_P outputs as critical

From: Michael Turquette
Date: Wed Dec 20 2017 - 12:27:01 EST

Quoting Dmitry Osipenko (2017-12-19 12:20:56)
> On 19.12.2017 22:56, Michael Turquette wrote:
> > Quoting Dmitry Osipenko (2017-12-18 19:59:06)
> >> Machine dies if HCLK, SCLK or EMC is disabled, hence mark these clocks
> >> as critical. Currently some of drivers do not manage clocks properly,
> >> expecting clocks to be 'always enabled', these clocks are MC and PLL_P
> >> outputs. Let's mark MC or PLL_P outputs as critical for now and revert
> >> this change once drivers would be corrected.
> >
> > Are the drivers that do not manage their clocks correctly merged
> > upstream? If so can we fix those drivers instead of marking clocks as
> > critical?
> All the drivers are in upstream for a quite long time already. We should be able
> to correct them, but I haven't tried yet.
> > If not can we annotate the flags below with a comment stating to remove
> > the critical clock flag once the consumer driver gets a clue?
> I'll try to take a look at how much effort it would take to correct the drivers
> during the next few days and will send v3 with either the comment being added or
> 'always enabled' clocks being dropped from the patch.

Great, thanks for looking into it. Critical clocks are an easy-to-abuse
feature and we should really be using the clk.h api as much as possible
in place of the critical clocks mechanism.

Best regards,