Messages in this thread | | | Date | Wed, 2 Nov 2022 11:52:39 +0100 | From | Johan Hovold <> | Subject | Re: [PATCH] clk: qcom: gdsc: Remove direct runtime PM calls |
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On Tue, Nov 01, 2022 at 04:34:21PM -0700, Stephen Boyd wrote: > We shouldn't be calling runtime PM APIs from within the genpd > enable/disable path for a couple reasons. > > First, this causes an AA lockdep splat because genpd can call into genpd > code again while holding the genpd lock. > > WARNING: possible recursive locking detected > 5.19.0-rc2-lockdep+ #7 Not tainted > -------------------------------------------- > kworker/2:1/49 is trying to acquire lock: > ffffffeea0370788 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x24/0x30 > > but task is already holding lock: > ffffffeea03710a8 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x24/0x30 > > other info that might help us debug this: > Possible unsafe locking scenario: > > CPU0 > ---- > lock(&genpd->mlock); > lock(&genpd->mlock); > > *** DEADLOCK *** > > May be due to missing lock nesting notation
I've seen this splat on sc8280xp as well but haven't had time to look into it yet.
> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > Cc: Johan Hovold <johan+linaro@kernel.org> > Cc: Ulf Hansson <ulf.hansson@linaro.org> > Cc: Taniya Das <quic_tdas@quicinc.com> > Cc: Satya Priya <quic_c_skakit@quicinc.com> > Cc: Douglas Anderson <dianders@chromium.org> > Cc: Matthias Kaehlcke <mka@chromium.org> > Reported-by: Stephen Boyd <swboyd@chromium.org>
We typically don't add Reported-by tags for bugs we find and fix ourselves.
> Fixes: 1b771839de05 ("clk: qcom: gdsc: enable optional power domain support") > Signed-off-by: Stephen Boyd <swboyd@chromium.org> > --- > drivers/clk/qcom/gdsc.c | 64 ++++++----------------------------------- > 1 file changed, 8 insertions(+), 56 deletions(-) > > diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c > index 7cf5e130e92f..a775ce1b7d8a 100644 > --- a/drivers/clk/qcom/gdsc.c > +++ b/drivers/clk/qcom/gdsc.c
> @@ -495,14 +451,11 @@ static int gdsc_init(struct gdsc *sc) > sc->pd.power_on = gdsc_enable; > > ret = pm_genpd_init(&sc->pd, NULL, !on); > - if (ret) > - goto err_put_rpm; > + if (!ret) > + goto err_disable_supply;
The logic should not be inverted here (and only happens to work currently when you have no regulator or the gdsc was off).
> return 0; > > -err_put_rpm: > - if (on) > - gdsc_pm_runtime_put(sc); > err_disable_supply: > if (on && sc->rsupply) > regulator_disable(sc->rsupply);
Johan
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