On Tue, Sep 15, 2020 at 06:05:22PM +0200, Krzysztof Kozlowski wrote:

On Mon, 14 Sep 2020 at 08:51, Dmitry Torokhov [off-list ref] wrote:

quoted

Hi Krzysztof,

On Fri, Aug 28, 2020 at 04:57:41PM +0200, Krzysztof Kozlowski wrote:

quoted

platform_get_irq() returns -ERRNO on error.  In such case comparison
to 0 would pass the check.

platform_get_irq() is a bit of a mess. Historically we allowed defining
interrupt resource with r->start == 0 and for such cases non-OF non-ACPI
code will return 0 from platform_get_irq() to indicate that IRQ is not
assigned.

We either need to stop doing this in platform_get_irq(), or the
conditions in this patch and followups should be "irq <= 0" and we need
to make sure we do not accidentally return 0 from probe ...

Hi,

It's then contradictory to platform_get_irq documentation which
explicitly says - zero will not be returned on error. This was also
clarified in commit e330b9a6bb35 ("platform: don't return 0 from
platform_get_irq[_byname]() on error").

It was for OF/ACPI, but not for resources described via DEFINE_RES_IRQ
or other means. However I see we added a big fat WARN_ON() in case if we
end up returning 0 still, so I will be applying your patches.

Thanks.

-- 
Dmitry