Re: [PATCH 2/5] thermal: qcom: Add support for LMh driver

[Thara Gopinath]

On 6/18/21 1:54 PM, Bjorn Andersson wrote:
> On Mon 14 Jun 20:38 CDT 2021, Thara Gopinath wrote:
> > On 6/14/21 4:53 PM, Bjorn Andersson wrote:
> > > On Tue 08 Jun 17:29 CDT 2021, Thara Gopinath wrote:
> > > > diff --git a/drivers/thermal/qcom/Makefile b/drivers/thermal/qcom/Makefile
> [..]
> > > > +static irqreturn_t lmh_handle_irq(int hw_irq, void *data)
> > > > +{
> > > > +	struct lmh_hw_data *lmh_data = data;
> > > > +	int irq = irq_find_mapping(lmh_data->domain, 0);
> > > > +
> > > > +	/*
> > > > +	 * Disable interrupt and call the cpufreq driver to handle the interrupt
> > > > +	 * cpufreq will enable the interrupt once finished processing.
> > > > +	 */
> > > > +	disable_irq_nosync(lmh_data->irq);
> > >
> > > The contract between this driver's disabling of the IRQ and the
> > > cpufreq-hw driver's enabling it when we're done polling does worry me.
> > >
> > > In the case of EPSS, don't we disable the interrupt during the polling
> > > there as well? If that's the case wouldn't it be better to implement
> > > irq_chip->irq_disable and have the cpufreq-hw driver do the disable in
> > > both cases?
> >
> > Yes. You are right. In case of EPSS, the cpufreq-hw will have to disable the
> > interrupt. I did think of the approach you suggested here. My only issue is
> > that we will dispatch the interrupt to cpufreq-hw without it disabling it
> > and hence the interrupt could fire again, right ?
>
> Does it fire again before you INTR_CLK it?

You mean clear it ? I couldn't reproduce it either way. I did not try 
the irq_chip->irq_disable either. So I will give it a try and if my 
tests pass , I will post it.

> Regards,
> Bjorn

--
Warm Regards
Thara (She/Her/Hers)