Re: [PATCH] Input: gpio-keys - add hibernation support

[Armando De Leon]

Hi Dmitry,

Thanks for the guidance. I investigated further:

The upstream GICv3 driver (irq-gic-v3.c) has no suspend/resume or
syscore_ops for the distributor - it does not save or restore any
per-IRQ configuration across power cycles. On platforms where the
GIC is re-initialized by firmware during hibernate restore, all
trigger type configurations set by consumer drivers during probe()
are lost.

The IRQ core does preserve the trigger type in irq_data
(irqd_get_trigger_type), but resume_irq() in kernel/irq/pm.c only
re-enables the interrupt without re-applying the trigger type to
hardware.

A fix in the IRQ PM resume path (having resume_irq() call
irq_set_irq_type() using the saved trigger type) would fix all
consumer drivers generically. However, such a change would have
broad consequences and impact across all platforms and interrupt
controllers, and would need very careful review and testing.

Given that the gpio-keys fix is a single irq_set_irq_type() call
in the .restore callback - minimal, self-contained, and low risk -
would it be acceptable to handle it at the driver level for now?
This avoids the risk of a sweeping IRQ core change while solving
the immediate problem for gpio-keys users with hibernation support.

Thanks,
Armando