Messages in this thread | | | Subject | Re: [PATCH] gpio: zynq: Implement irq_(request|release)_resources | From | Grygorii Strashko <> | Date | Tue, 27 Oct 2015 19:54:40 +0200 |
| |
On 10/27/2015 06:23 PM, Linus Walleij wrote: > On Tue, Oct 27, 2015 at 5:18 PM, Grygorii Strashko > <grygorii.strashko@ti.com> wrote: >> On 10/27/2015 05:53 PM, Linus Walleij wrote: >>> >>> On Fri, Oct 23, 2015 at 3:36 PM, Soren Brinkmann >>> <soren.brinkmann@xilinx.com> wrote: >>> >>>> The driver uses runtime PM to leverage low power techniques. For >>>> use-cases using GPIO as interrupt the device needs to be in an >>>> appropriate state. >>>> >>>> Reported-by: John Linn <linnj@xilinx.com> >>>> Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> >>>> Tested-by: John Linn <linnj@xilinx.com> >>> >>> >>> As pointed out by Grygorii in >>> commit aca82d1cbb49af34b69ecd4571a0fe48ad9247c1: >>> >>> The PM runtime API can't be used in atomic contex on -RT even if >>> it's configured as irqsafe. As result, below error report can >>> be seen when PM runtime API called from IRQ chip's callbacks >>> irq_startup/irq_shutdown/irq_set_type, because they are >>> protected by RAW spinlock: >>> (...) >>> The IRQ chip interface defines only two callbacks which are executed >>> in >>> non-atomic contex - irq_bus_lock/irq_bus_sync_unlock, so lets move >>> PM runtime calls there. >>> >>> I.e. these calls are atomic context and it's just luck that it works >>> and this is fragile. >>> >>> Can you please check if you can move it to >>> irq_bus_lock()/irq_sync_unlock() >>> like Grygorii does? >>> >> >> This patch rises the question not only about PM runtime, but also >> about gpiochip_irq_reqres()/gpiochip_irq_relres(). > > Do you mean that these functions contain calls to non-atomic > functions? >
Oh. No, I have to be more specific :( if GPIOx driver defines custom .irq_(request|release)_resources() callbacks they will *overwrite* standard GPIOirqchip callbacks. (commit: 8b67a1f "gpio: don't override irq_*_resources() callbacks")
As result, such GPIOx driver should *re-implement* the same functionality in its .irq_(request|release)_resources() callbacks as implemented in gpiochip_irq_reqres()/gpiochip_irq_relres().
> I mainly reacted to this because it was pm_* calls, that you > mentioned explicitly in your patch. > -- regards, -grygorii
| |