Re: [PATCH v3 2/4] irqchip/qcom-pdc: Switch to using IRQCHIP_PLATFORM_DRIVER helper macros

[Marc Zyngier]

On 2020-08-06 19:05, Saravana Kannan wrote:
> On Thu, Aug 6, 2020 at 5:12 AM Marc Zyngier <maz@xxxxxxxxxx> wrote:
> > On 2020-08-06 02:24, John Stultz wrote:

[...]

> > >> + if (par_np == np)
> > >> +         par_np = NULL;
> > >> +
> > >> + /*
> > >> + * If there's a parent interrupt controller and  none of the parent
> > >> irq
> > >> + * domains have been registered, that means the parent interrupt
> > >> + * controller has not been initialized yet.  it's not time for this
> > >> + * interrupt controller to initialize. So, defer probe of this
> > >> + * interrupt controller. The actual initialization callback of this
> > >> + * interrupt controller can check for specific domains as necessary.
> > >> + */
> > >> + if (par_np && !irq_find_matching_host(np, DOMAIN_BUS_ANY))
> > >> +         return -EPROBE_DEFER;
> > >
> > > Yep. We're getting caught on the irq_find_matching_host() check. I'm a
> > > little lost as when I look at the qcom,pdc node in the dtsi its not
> > > under a parent controller (instead the soc node).
> > > Not sure if that's an issue in the dtsi or if par_np check needs to
> > > ignore the soc node and pass null?
> >
> > I think you have nailed it. This checks for a domain attached to
> > the driver we are about to probe, and this domain cannot possibly
> > exist. Instead, it is the *parent* this should check for, as we
> > depend on it for successful probing.
>
> Duh! Looks like I made a copy-paste/typo error. The comment clearly
> says I'm trying to check the parent and then I end up checking the
> node getting registered. I'm sure this will fix it.
>
> Actually Nial sent an email a few hours after your and he had found
> the same issue. He even tested the fix with an irqchip driver and it
> fixed the probe issue.

OK, thanks for confirming. It would have been good if these patches
had seen a bit more testing.

> I'm assuming you'll put up the patch yourself. Please let me know if
> you need me to send one.

I have queued this [1] in -next.

It'd be good if someone (John?) could give a Tested-by.

Thanks,

        M.

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=irq/irqchip-next
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