[PATCH] phy: renesas: phy-rzg3e-usb3: Fix runtime PM underflow during suspend

[Geert Uytterhoeven]

Hi Ovidiu,

On Mon, 4 May 2026 at 13:11, Ovidiu Panait <ovidiu.panait.rb at renesas.com> wrote:
> > On 27-04-26, 19:47, Ovidiu Panait wrote:
> > > On the Renesas RZ/V2H platform, if the xhcd driver is unbound and the
> > > system is suspended afterwards, a PM underflow error will occur:
> > >
> > >  # echo 15850000.usb > /sys/bus/platform/drivers/xhci-renesas-hcd/unbind
> > >  # systemctl suspend
> > >  15870000.usb-phy: PM: dpm_run_callback(): genpd_resume_noirq returns -
> > 13
> > >  15870000.usb-phy: PM: failed to resume noirq: error -13
> > >  15870000.usb-phy: Runtime PM usage count underflow!
> > >
> > > Since the PHY framework is managing the runtime PM of the PHY via
> > > phy_power_on()/phy_power_off(), there is no need for the PHY driver to
> > > manipulate the runtime PM state during suspend.
> > >
> > > To fix this, remove the runtime PM calls from the suspend/resume paths
> > > and add a get/put pair inside rzg3e_phy_usb3_init_helper() to make sure
> > > the clock is enabled during init, even when there is no consumer for
> > > the PHY.
> >
> > > Also, change the suspend ops from NOIRQ_SYSTEM_SLEEP_PM_OPS to
> > > SYSTEM_SLEEP_PM_OPS because runtime PM is disabled during the noirq
> > phase
> > > and pm_runtime_resume_and_get() would not actually enable the device
> > clock.
> >
> > > Fixes: ee5f1a3f90a4 ("phy: renesas: Add Renesas RZ/G3E USB3.0 PHY
> > driver")
> > > Signed-off-by: Ovidiu Panait <ovidiu.panait.rb at renesas.com>

> > > index 6b3453ea0004..055775e1a0f7 100644
> > > --- a/drivers/phy/renesas/phy-rzg3e-usb3.c
> > > +++ b/drivers/phy/renesas/phy-rzg3e-usb3.c

> > > @@ -215,27 +226,21 @@ static int rzg3e_phy_usb3_resume(struct device
> > *dev)
> > >     if (ret)
> > >             return ret;
> > >
> > > -   ret = pm_runtime_resume_and_get(dev);
> > > +   ret = rzg3e_phy_usb3_init_helper(r);
> > >     if (ret)
> > >             goto reset_assert;
> > >
> > > -   ret = rzg3e_phy_usb3_init_helper(r->base);
> > > -   if (ret)
> > > -           goto pm_put;
> > > -
> > >     r->skip_reinit = true;
> >
> > https://sashiko.dev/#/patchset/20260427194741.161533-1-
> > ovidiu.panait.rb%40renesas.com
> >
>
> I think this is not applicable for our platforms, as the power domain only
> gates the clock during runtime suspend, so the register state is not lost
> across runtime suspend/resume.
>
> The power domain (drivers/clk/renesas/rzv2h-cpg.c) is marked as
> GENPD_FLAG_ALWAYS_ON.

Won't the SoC be powered down during s2ram?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds