linux-kernel - Re: [PATCH] clk: qcom: rpmh: Set wake/sleep state for BCM clks

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Date:   Wed, 11 May 2022 15:04:12 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        patches@...ts.linux.dev, Alex Elder <elder@...aro.org>,
        Taniya Das <quic_tdas@...cinc.com>
Subject: Re: [PATCH] clk: qcom: rpmh: Set wake/sleep state for BCM clks

Quoting Stephen Boyd (2022-05-06 16:24:15)
> Quoting Bjorn Andersson (2022-05-04 09:53:54)
> > On Tue 12 Apr 14:45 CDT 2022, Stephen Boyd wrote:
> >
> > > Set the wake and sleep state for BCM clks here, not just the active
> > > state, as the active only state is dropped when CPUs go to deep idle.
> > > This ensures the clk is always on when the driver thinks it is on.
> > >
> > > This was found by inspection, and could very well be incorrect if the
> > > RPMh hardware copies over the active only state to the sleep and wake
> > > states.
> > >
> >
> > Taking another look at this patch and now it makes perfect sense to me.
> > Sorry for not grasping the problem earlier.
> >
> > Reviewed-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> >
> >
> > Will you take this in fixes, or do you want me to pick it for 5.19?
> >
>
> I'm waiting for Taniya to reply. For all I know this has no effect
> because there's some sort of copy/paste from one state to another. Until
> then it doesn't seem like we should do anything.

Taniya told me that if there's no sleep or wake state set then active
state remains even when the subsystem is in sleep. Not exactly
copy/paste but at least it is consistent. We need a comment here so this
doesn't come up again.