Re: [PATCH] gpiolib: handle probe deferrals better

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Mon, Apr 4, 2016 at 6:21 PM, Grygorii Strashko
<grygorii.strashko@xxxxxx> wrote:

> Below is RFC patch to prove above consent. I've had offlist
> debugging session with Alexander and He mentioned that this change
> fixes boot issue for him.

Thanks for looking into this.

> Of course, there are some question to discuss:
> 1) [+] It should sync initialization of GPIOchip and GPIOirqchip
> 2) [+] This approach requires changes in gpiolib/gpio drivers only, from other side
> It will require to add fixes all over the Kernel if gpiod_to_irq() will
> start returning -EPROBE_DEFER.

Yes, so it will need to be cross-coordinated with IRQ maintainers
Marc and TGLX.

> 3) [-] has_irq might need to be initialized by non-DT drivers

Yes. Every driver in the kernel need to be audited.

> 4) [-] irq_ready might need to be set manually by drivers which do not use GPIO irq
>    helpers (see change in gpio-mpc8xxx.c)

Yes. That too. Every driver in the kernel need to be audited.

> 4) irq_ready access synchronization on SMP? atomic?

Uhhh.... I don't even understand the question.

> job done with commit e6918cd 'gpiolib: handle probe deferrals better'
> reverted.

I have taken that out of my tree as well. My naive approach
doesn't work.

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html