Hi Arnd,
On 12/02/2021 11:45, Arnd Bergmann wrote:
On Fri, Feb 12, 2021 at 6:05 AM Song Bao Hua (Barry Song)
<song.bao.hua@xxxxxxxxxxxxx> wrote:
-----Original Message-----
Note. there is also generic_handle_irq() call inside.
So generic_handle_irq() is not safe to run in thread thus requires
an interrupt-disabled environment to run? If so, I'd rather this
irqsave moved into generic_handle_irq() rather than asking everyone
calling it to do irqsave.
In a preempt-rt kernel, interrupts are run in task context, so they clearly
should not be called with interrupts disabled, that would defeat the
purpose of making them preemptible.
generic_handle_irq() does need to run with in_irq()==true though,
but this should be set by the caller of the gpiochip's handler, and
it is not set by raw_spin_lock_irqsave().
It will produce warning from __handle_irq_event_percpu(), as this is IRQ dispatcher
and generic_handle_irq() will call one of handle_level_irq or handle_edge_irq.
The history behind this is commit 450fa54cfd66 ("gpio: omap: convert to use generic irq handler").
The resent related discussion:
https://lkml.org/lkml/2020/12/5/208
--
Best regards,
grygorii
