Re: [PATCH] rtc: interface: set the next alarm event appropriately

From: Alexandre Belloni
Date: Wed Sep 20 2017 - 05:16:28 EST


Hi,

On 20/09/2017 at 11:22:31 +0800, Xu Yiping wrote:
> From: Xu YiPing <xuyiping@xxxxxxxxxxxxx>
>
> After commit 2b2f5ff00f63 ("rtc: interface: ignore expired timers when
> enqueuing new timers"), the rtc_timer_enqueue will not reprogram the RTC
> when there is any non-expired timers in the timerqueue. If we set a
> RTC_TIMER between now and the next non-expired timers, it won't go into
> effect in time.
>
> So, besides ignoring the expired timers, we should take the next effect
> timer into account, and reprogram the RTC timer appropriately.
>

Can you try this patch instead? I think it solves this issue:
http://patchwork.ozlabs.org/patch/792482/

> Signed-off-by: Xu YiPing <xuyiping@xxxxxxxxxxxxx>
> Signed-off-by: Chen Jun <roy.chenjun@xxxxxxxxxxxxx>
> ---
> drivers/rtc/interface.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
> index 8cec9a0..e237166 100644
> --- a/drivers/rtc/interface.c
> +++ b/drivers/rtc/interface.c
> @@ -766,20 +766,23 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
> struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
> struct rtc_time tm;
> ktime_t now;
> + ktime_t next_effect = KTIME_MAX;
>
> timer->enabled = 1;
> __rtc_read_time(rtc, &tm);
> now = rtc_tm_to_ktime(tm);
>
> - /* Skip over expired timers */
> + /* Skip over expired timers, get next effect timer */
> while (next) {
> - if (next->expires >= now)
> + if (next->expires >= now) {
> + next_effect = next->expires;
> break;
> + }
> next = timerqueue_iterate_next(next);
> }
>
> timerqueue_add(&rtc->timerqueue, &timer->node);
> - if (!next) {
> + if (timer->node.expires < next_effect) {
> struct rtc_wkalrm alarm;
> int err;
> alarm.time = rtc_ktime_to_tm(timer->node.expires);
> --
> 2.7.4
>

--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com