From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Rajendra Nayak <rnayak@codeaurora.org>
Cc: Andy Gross <agross@kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Stephen Boyd <swboyd@chromium.org>,
Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] soc: qcom: rpmhpd: Use corner in power_off
Date: Tue, 6 Jul 2021 23:49:10 -0500 [thread overview]
Message-ID: <YOUyRrvdPLkbTqUp@yoga> (raw)
In-Reply-To: <c4440f5e-592c-b849-3ca7-57e812de2df5@codeaurora.org>
On Mon 05 Jul 00:40 CDT 2021, Rajendra Nayak wrote:
> On 7/5/2021 10:36 AM, Bjorn Andersson wrote:
> > On Sun, Jul 4, 2021 at 11:27 PM Rajendra Nayak <rnayak@codeaurora.org> wrote:
> > >
> > >
> > >
> > > On 7/3/2021 6:24 AM, Bjorn Andersson wrote:
> > > > rpmhpd_aggregate_corner() takes a corner as parameter, but in
> > > > rpmhpd_power_off() the code requests the level of the first corner
> > > > instead.
> > > >
> > > > In all (known) current cases the first corner has level 0, so this
> > > > change should be a nop, but in case that there's a power domain with a
> > > > non-zero lowest level this makes sure that rpmhpd_power_off() actually
> > > > requests the lowest level - which is the closest to "power off" we can
> > > > get.
> > > >
> > > > While touching the code, also skip the unnecessary zero-initialization
> > > > of "ret".
> > > >
> > > > Fixes: 279b7e8a62cc ("soc: qcom: rpmhpd: Add RPMh power domain driver")
> > > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > > > ---
> > > > drivers/soc/qcom/rpmhpd.c | 5 ++---
> > > > 1 file changed, 2 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/drivers/soc/qcom/rpmhpd.c b/drivers/soc/qcom/rpmhpd.c
> > > > index 2daa17ba54a3..fa209b479ab3 100644
> > > > --- a/drivers/soc/qcom/rpmhpd.c
> > > > +++ b/drivers/soc/qcom/rpmhpd.c
> > > > @@ -403,12 +403,11 @@ static int rpmhpd_power_on(struct generic_pm_domain *domain)
> > > > static int rpmhpd_power_off(struct generic_pm_domain *domain)
> > > > {
> > > > struct rpmhpd *pd = domain_to_rpmhpd(domain);
> > > > - int ret = 0;
> > > > + int ret;
> > > >
> > > > mutex_lock(&rpmhpd_lock);
> > > >
> > > > - ret = rpmhpd_aggregate_corner(pd, pd->level[0]);
> > > > -
> > > > + ret = rpmhpd_aggregate_corner(pd, 0);
> > >
> > > This won't work for cases where pd->level[0] != 0, rpmh would just ignore this and keep the
> > > resource at whatever corner it was previously at.
> > > (unless command DB tells you a 0 is 'valid' for a resource, sending a 0 is a nop)
> > > The right thing to do is to send in whatever command DB tells you is the lowest level that's valid,
> > > which is pd->level[0].
> > >
> >
> > I'm afraid this doesn't make sense to me.
> >
> > In rpmh_power_on() if cmd-db tells us that we have [0, 64, ...] and we
> > request 64 we rpmhpd_aggregate_corner(pd, 1); but in power off, if
> > cmd-db would provide [64, ...] we would end up sending
> > rpmhpd_aggregate_corner(pd, 64);
> > So in power_on we request the corner (i.e. index in the array provided
> > in cmd-db) and in power-off the same function takes the level?
>
> ah that's right, I did not read the commit log properly and got confused.
Thanks for confirming my understanding.
> Looks like this bug existed from the day this driver for merged :/, thanks
> for catching it.
> Does it make sense to also mark this fix for stable?
>
I can certainly add a Cc: stable@ as I'm applying this.
May I have your R-b?
PS. Do you have any input on patch 2/2? That actually solves a practical
problem we're seeing. Would it perhaps aid in your need for the new
"assigned-opp-level" property?
Regards,
Bjorn
next prev parent reply other threads:[~2021-07-07 4:49 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-03 0:54 [PATCH 0/2] soc: qcom: rpmhpd: Improve rpmhpd enable handling Bjorn Andersson
2021-07-03 0:54 ` [PATCH 1/2] soc: qcom: rpmhpd: Use corner in power_off Bjorn Andersson
2021-07-05 4:26 ` Rajendra Nayak
2021-07-05 5:06 ` Bjorn Andersson
2021-07-05 5:40 ` Rajendra Nayak
2021-07-07 4:49 ` Bjorn Andersson [this message]
2021-07-07 6:31 ` Rajendra Nayak
2021-07-07 15:48 ` Bjorn Andersson
2021-07-07 16:58 ` Dmitry Baryshkov
2021-07-08 0:21 ` Stephen Boyd
2021-07-08 4:35 ` Bjorn Andersson
2021-07-08 5:03 ` Rajendra Nayak
2021-07-08 6:51 ` Stephen Boyd
2021-07-15 10:40 ` Sibi Sankar
2021-07-03 0:54 ` [PATCH 2/2] soc: qcom: rpmhpd: Make power_on actually enable the domain Bjorn Andersson
2021-07-03 2:54 ` [RESEND PATCH " Bjorn Andersson
2021-07-08 0:23 ` Stephen Boyd
2021-07-08 0:25 ` Stephen Boyd
2021-07-14 9:22 ` Rajendra Nayak
2021-07-15 12:16 ` Sibi Sankar
2021-07-15 12:24 ` Rajendra Nayak
2021-08-12 13:21 ` Dmitry Baryshkov
2021-08-13 9:45 ` Ulf Hansson
2021-07-05 12:55 ` [PATCH 0/2] soc: qcom: rpmhpd: Improve rpmhpd enable handling Ulf Hansson
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