Re: [PATCH v1] gpio: pca953x: fix IRQ storm on system wake up

From: Andy Shevchenko
Date: Thu Apr 03 2025 - 09:56:32 EST


+Cc: Geert

On Thu, Apr 03, 2025 at 02:07:05PM +0200, Bartosz Golaszewski wrote:
> On Wed, 26 Mar 2025 18:38:38 +0100, Francesco Dolcini wrote:

> > If an input changes state during wake-up and is used as an interrupt
> > source, the IRQ handler reads the volatile input register to clear the
> > interrupt mask and deassert the IRQ line. However, the IRQ handler is
> > triggered before access to the register is granted, causing the read
> > operation to fail.
> >
> > As a result, the IRQ handler enters a loop, repeatedly printing the
> > "failed reading register" message, until `pca953x_resume` is eventually
> > called, which restores the driver context and enables access to
> > registers.

[...]

> Applied, thanks!

Won't this regress as it happens the last time [1]?

[1]: https://lore.kernel.org/linux-gpio/CAMuHMdVnKX23yi7ir1LVxfXAMeeWMFzM+cdgSSTNjpn1OnC2xw@xxxxxxxxxxxxxx/

--
With Best Regards,
Andy Shevchenko