[Xenomai] Gpio: IRQ handler is called ~4ms after state change

Lennart Sorensen lsorense at csclub.uwaterloo.ca
Wed Jun 21 20:28:03 CEST 2017


On Tue, Jun 20, 2017 at 03:03:33PM +0000, Giulio Moro wrote:
> Thanks Len,
> 
> > Turns out that in that case smartidle was enabled and the gpio bank
> >  would go into sleep mode and it took 4ms to wake up before the irq would
> > show up.  Turning off the smartidle on the gpio bank so that it never
> > could go to sleep solved the problem.  Maybe this TI chip has a similar
> > feature.
> 
> I do not think it is the case in my test: the GPIO banks are on (the pins get exported before the module is loaded), and I would not expect it to go to sleep in the few ms between interrupts in my test.

Based on my experience with the newer TI, it will.  For the auto power
saving bit, miliseconds is a long time.

I fixed it by setting the gpio-bank to ti,no-idle in the dtb.

-- 
Len Sorensen



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