[regression] mhi: ath11k resume fails on some devices

[Manivannan Sadhasivam]

On Thu, Oct 07, 2021 at 12:55:52PM +0300, Kalle Valo wrote:
> (adding also mhi list)
> 
> Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org> writes:
> 
> > On Fri, Sep 24, 2021 at 12:07:41PM +0300, Kalle Valo wrote:
> >> Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org> writes:
> >> 
> >> > For aid debugging, please see the state the device is in during mhi_pm_resume().
> >> > You can use below diff:
> >> >
> >> > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> >> > index fb99e3727155..482d55dd209e 100644
> >> > --- a/drivers/bus/mhi/core/pm.c
> >> > +++ b/drivers/bus/mhi/core/pm.c
> >> > @@ -898,6 +898,9 @@ int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
> >> >         if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
> >> >                 return -EIO;
> >> >  
> >> > +       dev_info(dev, "Device state: %s\n",
> >> > +                TO_MHI_STATE_STR(mhi_get_mhi_state(mhi_cntrl)));
> >> > +
> >> >         if (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_M3)
> >> >                 return -EINVAL;
> >> 
> >> This is what I get with my NUC testbox:
> >> 
> >> [  970.488202] ACPI: EC: event unblocked
> >> [  970.492484] hpet: Lost 1587 RTC interrupts
> >> [  970.492749] mhi mhi0: Device state: RESET
> >
> > Looks like the MHI device went into RESET state! It also looks to be a
> > firmware thing. But let's nail this down before adding any workaround in
> > the MHI stack.
> >
> > Can you also rebuild the kernel with MHI debug enabled and capture the
> > logs in faliure case?
> 
> So what I should exactly do to enable debug messages?
> 
> I have this in my Kconfig:
> 
> CONFIG_MHI_BUS=m
> # CONFIG_MHI_BUS_DEBUG is not set
> # CONFIG_MHI_BUS_PCI_GENERIC is not set
> 
> And AFAICS CONFIG_MHI_BUS_DEBUG only enables the debugfs interface, I
> doubt you meant that.
> 

No. You should enable the dev_dbg messages in MHI core by adding the -DDEBUG
flag to the Makefile or by CONFIG_DYNAMIC_DEBUG.

Thanks,
Mani

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