Hi,
On Tue, Sep 22, 2020 at 1:07 AM Matthias Brugger <matthias....@gmail.com> wrote:
>
> Hi Nicolas,
>
> Thanks for the patch.
>
> On 30/07/2020 06:01, Nicolas Boichat wrote:
> > In the error case, where a power domain cannot be powered on
> > successfully at boot time (in mtk_register_power_domains),
> > pm_genpd_init would still be called with is_off=false, and the
> > system would later try to disable the power domain again, triggering
> > warnings as disabled clocks are disabled again (and other potential
> > issues).
> >
> > Fixes: c84e358718a66f7 ("soc: Mediatek: Add SCPSYS power domain driver")
> > Signed-off-by: Nicolas Boichat <drink...@chromium.org>
> >
> > ---
> >
> > drivers/soc/mediatek/mtk-scpsys.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/soc/mediatek/mtk-scpsys.c
> > b/drivers/soc/mediatek/mtk-scpsys.c
> > index f669d3754627dad..0055a52a49733d5 100644
> > --- a/drivers/soc/mediatek/mtk-scpsys.c
> > +++ b/drivers/soc/mediatek/mtk-scpsys.c
> > @@ -524,6 +524,7 @@ static void mtk_register_power_domains(struct
> > platform_device *pdev,
> > for (i = 0; i < num; i++) {
> > struct scp_domain *scpd = &scp->domains[i];
> > struct generic_pm_domain *genpd = &scpd->genpd;
> > + bool on;
> >
> > /*
> > * Initially turn on all domains to make the domains usable
> > @@ -531,9 +532,9 @@ static void mtk_register_power_domains(struct
> > platform_device *pdev,
> > * software. The unused domains will be switched off during
> > * late_init time.
> > */
> > - genpd->power_on(genpd);
> > + on = genpd->power_on(genpd) >= 0;
>
> Is this something we expect? On probing we realize that some domains can't be
> turned on?
>
> I understand that this would be a bug in the driver. Therefore we should at
> most
> provide a warning instead of working around the bug, hiding it. Or do I got
> this
> wrong?
No, you get this right. That's a bug (we see this on unreleased HW),
and we will fix it.
Now, we already get this (somewhat subtle) error message on boot:
mtk-scpsys 10006000.power-controller: Failed to power on domain adsp
But without this patch, there is an unbalance later on (that is
possibly a bit confusing):
[ 6.510811] ------------[ cut here ]------------
[ 6.515417] adsp_sel already disabled
[ 6.519089] WARNING: CPU: 5 PID: 180 at drivers/clk/clk.c:958
clk_core_disable+0x1ec/0x22c
...
[ 6.658393] clk_core_disable+0x1ec/0x22c
[ 6.662395] clk_disable+0x34/0x48
[ 6.665791] scpsys_clk_disable+0x34/0x58
[ 6.669791] scpsys_power_off+0x374/0x3ec
[ 6.673790] _genpd_power_off+0x40/0x98
[ 6.677616] genpd_power_off+0x168/0x208
[ 6.681530] genpd_power_off_work_fn+0x38/0x54
[ 6.685964] process_one_work+0x208/0x3c8
[ 6.689964] worker_thread+0x23c/0x3e8
[ 6.693703] kthread+0x11c/0x12c
[ 6.696923] ret_from_fork+0x10/0x18
[ 6.700487] ---[ end trace 91ddada49c4d717c ]---
But I get your point, we should probably add something like
WARN_ON(!on) to make it clearer, at the time when the issue occurs,
that something is not right...
Thanks,
> Regards,
> Matthias
>
> >
> > - pm_genpd_init(genpd, NULL, false);
> > + pm_genpd_init(genpd, NULL, !on);
> > }
> >
> > /*
> >
