Re: [PATCH 33/36] cpuidle,omap3: Use WFI for omap3_pm_idle()

From: Peter Zijlstra
Date: Thu Jun 09 2022 - 05:41:28 EST


On Wed, Jun 08, 2022 at 06:28:33PM +0200, Arnd Bergmann wrote:
> On Wed, Jun 8, 2022 at 4:27 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> >
> > arch_cpu_idle() is a very simple idle interface and exposes only a
> > single idle state and is expected to not require RCU and not do any
> > tracing/instrumentation.
> >
> > As such, omap_sram_idle() is not a valid implementation. Replace it
> > with the simple (shallow) omap3_do_wfi() call. Leaving the more
> > complicated idle states for the cpuidle driver.
> >
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
>
> I see similar code in omap2:
>
> omap2_pm_idle()
> -> omap2_enter_full_retention()
> -> omap2_sram_suspend()
>
> Is that code path safe to use without RCU or does it need a similar change?

It needs a similar change, clearly I was running on fumes to not have
found that when grepping around the omap code :/