Re: [PATCH] gpio: omap: use raw locks for locking

[Linus Walleij <linus.walleij@linaro.org>]

On Thu, Feb 12, 2015 at 5:10 PM, Sebastian Andrzej Siewior
<bigeasy@linutronix.de> wrote:

> This patch converts gpio_bank.lock from a spin_lock into a
> raw_spin_lock. The call path to access this lock is always under a
> raw_spin_lock, for instance
> - __setup_irq() holds &desc->lock with irq off
>   + __irq_set_trigger()
>    + omap_gpio_irq_type()
>
> - handle_level_irq() (runs with irqs off therefore raw locks)
>   + mask_ack_irq()
>    + omap_gpio_mask_irq()
>
> This fixes the obvious backtrace on -RT. However I noticed two cases
> where it looks wrong and this is not limited to -RT:
> - omap_gpio_irq_type() is called with IRQ off and has an conditional
>   call to pm_runtime_get_sync() which may sleep. Either it may happen or
>   it may not happen but pm_runtime_get_sync() should not be called in an
>   atomic section.
>
> - omap_gpio_debounce() is holding the lock with IRQs off.
>   + omap2_set_gpio_debounce()
>    + clk_prepare_enable()
>     + clk_prepare() this one might sleep.
>   The number of users of gpiod_set_debounce() / gpio_set_debounce()
>   looks low but still this is not good.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

This doesn't apply to the current development tree.

Can you rebase this patch in Torvalds' HEAD, add Javier's ACK
and resend?

Please put me on the To: line, I have no time to read all mail that
I'm only CC on.

Yours,
Linus Walleij