[regression] mhi: ath11k resume fails on some devices

[Kalle Valo]

(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.

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