Re: [PATCH] rtc: rtc-omap: Replace mdelay() with msleep() in omap_rtc_power_off()
From: Johan Hovold
Date: Tue Aug 28 2018 - 04:49:48 EST
On Mon, Aug 27, 2018 at 10:55:17PM +0200, Alexandre Belloni wrote:
> On 30/07/2018 21:53:14+0800, Jia-Ju Bai wrote:
> > omap_rtc_power_off() is never called in atomic context.
> > It calls mdelay() to busily wait, which is not necessary.
> > mdelay() can be replaced with msleep().
> > This is found by a static analysis tool named DCNS written by myself.
> > Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
> > ---
> > drivers/rtc/rtc-omap.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> > diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
> > index 39086398833e..ef3d09525d0f 100644
> > --- a/drivers/rtc/rtc-omap.c
> > +++ b/drivers/rtc/rtc-omap.c
> > @@ -476,7 +476,7 @@ static void omap_rtc_power_off(void)
> > * power off the system. Add a 500 ms margin for external latencies
> > * (e.g. debounce circuits).
> > */
> > - mdelay(2500);
> > + msleep(2500);
> I'm not sure about that one because this is a poweroff function so it
> doesn't really make sense to sleep versus busy waiting (all the drivers
> in power/reset use mdelay())
This power-off handler is called with interrupts disabled (as mentioned
in the function header) and must not sleep.