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

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Date:   Wed, 20 Sep 2017 17:36:10 +0800
From:   YiPing Xu <xuyiping@...ilicon.com>
To:     Alexandre Belloni <alexandre.belloni@...e-electrons.com>
CC:     <a.zummo@...ertech.it>, <linux-rtc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <roy.chenjun@...ilicon.com>,
        <colin.king@...onical.com>, <wanghao24@...wei.com>
Subject: Re: [PATCH] rtc: interface: set the next alarm event appropriately

Hi,

On 2017/9/20 17:16, Alexandre Belloni wrote:
> Hi,
>
> On 20/09/2017 at 11:22:31 +0800, Xu Yiping wrote:
>> From: Xu YiPing  <xuyiping@...ilicon.com>
>>
>> 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/

it looks work.

will it be merged into the main tree ?

>> Signed-off-by: Xu YiPing <xuyiping@...ilicon.com>
>> Signed-off-by: Chen Jun <roy.chenjun@...ilicon.com>
>> ---
>>  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
>>
>