[PATCH] selftests: breakpoints: check RTC wakeup alarm support before test

[PATCH] selftests: breakpoints: check RTC wakeup alarm support before test

[Xinyu Zheng]

If RTC wakeup alarm feature is unsupported, this testcase may cause
infinite suspend if there is no other wakeup source. To solve this
problem, set wakeup alarm up before we trigger suspend. In this case,
we can test if RTC support RTC_FEATURE_ALARM and efi_set_alarm function.

Signed-off-by: Xinyu Zheng <zhengxinyu6@huawei.com>
---
 .../breakpoints/step_after_suspend_test.c     | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/tools/testing/selftests/breakpoints/step_after_suspend_test.c b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
index 8d233ac95696..e738af896ce1 100644
--- a/tools/testing/selftests/breakpoints/step_after_suspend_test.c
+++ b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
@@ -13,6 +13,8 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
+#include <linux/rtc.h>
+#include <sys/ioctl.h>
 #include <sys/ptrace.h>
 #include <sys/stat.h>
 #include <sys/timerfd.h>
@@ -159,10 +161,30 @@ void suspend(void)
 	int count_before;
 	int count_after;
 	struct itimerspec spec = {};
+	char *rtc_file = "/dev/rtc0";
+	int rtc_fd;
+	struct rtc_wkalrm alarm = { 0 };
+	time_t secs;
 
 	if (getuid() != 0)
 		ksft_exit_skip("Please run the test as root - Exiting.\n");
 
+	rtc_fd = open(rtc_file, O_RDONLY);
+	if (rtc_fd < 0)
+		ksft_exit_fail_msg("open rtc0 failed\n");
+
+	err = ioctl(rtc_fd, RTC_RD_TIME, &alarm.time);
+	if (err < 0)
+		ksft_exit_fail_msg("get rtc time failed\n");
+
+	secs = timegm((struct tm *)&alarm.time) + 3;
+	gmtime_r(&secs, (struct tm *)&alarm.time);
+	alarm.enabled = 1;
+
+	err = ioctl(rtc_fd, RTC_WKALM_SET, &alarm);
+	if (err < 0)
+		ksft_exit_fail_msg("set wake alarm test failed, errno %d\n", errno);
+
 	timerfd = timerfd_create(CLOCK_BOOTTIME_ALARM, 0);
 	if (timerfd < 0)
 		ksft_exit_fail_msg("timerfd_create() failed\n");
@@ -180,6 +202,7 @@ void suspend(void)
 	if (count_after <= count_before)
 		ksft_exit_fail_msg("Failed to enter Suspend state\n");
 
+	close(rtc_fd);
 	close(timerfd);
 }
 
-- 
2.34.1

Re: [PATCH] selftests: breakpoints: check RTC wakeup alarm support before test

[Shuah Khan]

On 11/11/25 23:15, Xinyu Zheng wrote:
> If RTC wakeup alarm feature is unsupported, this testcase may cause

It may cause infinite suspend? Doesn't sound definitive.> infinite suspend if there is no other wakeup source. To solve this
> problem, set wakeup alarm up before we trigger suspend. In this case,
> we can test if RTC support RTC_FEATURE_ALARM and efi_set_alarm function.
> 

For a "may cause" problem, this change> Signed-off-by: Xinyu Zheng <zhengxinyu6@huawei.com>
> --->   .../breakpoints/step_after_suspend_test.c     | 23 +++++++++++++++++++
>   1 file changed, 23 insertions(+)
> 
> diff --git a/tools/testing/selftests/breakpoints/step_after_suspend_test.c b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
> index 8d233ac95696..e738af896ce1 100644
> --- a/tools/testing/selftests/breakpoints/step_after_suspend_test.c
> +++ b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
> @@ -13,6 +13,8 @@
>   #include <stdio.h>
>   #include <string.h>
>   #include <unistd.h>
> +#include <linux/rtc.h>
> +#include <sys/ioctl.h>
>   #include <sys/ptrace.h>
>   #include <sys/stat.h>
>   #include <sys/timerfd.h>
> @@ -159,10 +161,30 @@ void suspend(void)
>   	int count_before;
>   	int count_after;
>   	struct itimerspec spec = {};
> +	char *rtc_file = "/dev/rtc0";
> +	int rtc_fd;
> +	struct rtc_wkalrm alarm = { 0 };
> +	time_t secs;
>   
>   	if (getuid() != 0)
>   		ksft_exit_skip("Please run the test as root - Exiting.\n");
>   
> +	rtc_fd = open(rtc_file, O_RDONLY);
> +	if (rtc_fd < 0)
> +		ksft_exit_fail_msg("open rtc0 failed\n");
> +
> +	err = ioctl(rtc_fd, RTC_RD_TIME, &alarm.time);
> +	if (err < 0)
> +		ksft_exit_fail_msg("get rtc time failed\n");
> +
> +	secs = timegm((struct tm *)&alarm.time) + 3;
> +	gmtime_r(&secs, (struct tm *)&alarm.time);
> +	alarm.enabled = 1;
> +
> +	err = ioctl(rtc_fd, RTC_WKALM_SET, &alarm);
> +	if (err < 0)
> +		ksft_exit_fail_msg("set wake alarm test failed, errno %d\n", errno);

Essentially with this change the test doesn't run unless
RTC wake is supported. That sounds restrictive - is there
another way do do this?

> +
>   	timerfd = timerfd_create(CLOCK_BOOTTIME_ALARM, 0);
>   	if (timerfd < 0)
>   		ksft_exit_fail_msg("timerfd_create() failed\n");
> @@ -180,6 +202,7 @@ void suspend(void)
>   	if (count_after <= count_before)
>   		ksft_exit_fail_msg("Failed to enter Suspend state\n");
>   
> +	close(rtc_fd);
>   	close(timerfd);
>   }
>  
thanks,
-- Shuah

Re: [PATCH] selftests: breakpoints: check RTC wakeup alarm support before test

[Xinyu Zheng]

On 11/20/2025 6:15 AM, Shuah Khan wrote:
> On 11/11/25 23:15, Xinyu Zheng wrote:
>> If RTC wakeup alarm feature is unsupported, this testcase may cause
> 
> It may cause infinite suspend? Doesn't sound definitive.> infinite 
> suspend if there is no other wakeup source. To solve this
>> problem, set wakeup alarm up before we trigger suspend. In this case,
>> we can test if RTC support RTC_FEATURE_ALARM and efi_set_alarm function.
>>
> 
> For a "may cause" problem, this change> Signed-off-by: Xinyu Zheng 
> <zhengxinyu6@huawei.com>
>> --->   .../breakpoints/step_after_suspend_test.c     | 23 ++++++++++++ 
>> +++++++
>>   1 file changed, 23 insertions(+)
>>
>> diff --git a/tools/testing/selftests/breakpoints/ 
>> step_after_suspend_test.c b/tools/testing/selftests/breakpoints/ 
>> step_after_suspend_test.c
>> index 8d233ac95696..e738af896ce1 100644
>> --- a/tools/testing/selftests/breakpoints/step_after_suspend_test.c
>> +++ b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
>> @@ -13,6 +13,8 @@
>>   #include <stdio.h>
>>   #include <string.h>
>>   #include <unistd.h>
>> +#include <linux/rtc.h>
>> +#include <sys/ioctl.h>
>>   #include <sys/ptrace.h>
>>   #include <sys/stat.h>
>>   #include <sys/timerfd.h>
>> @@ -159,10 +161,30 @@ void suspend(void)
>>       int count_before;
>>       int count_after;
>>       struct itimerspec spec = {};
>> +    char *rtc_file = "/dev/rtc0";
>> +    int rtc_fd;
>> +    struct rtc_wkalrm alarm = { 0 };
>> +    time_t secs;
>>       if (getuid() != 0)
>>           ksft_exit_skip("Please run the test as root - Exiting.\n");
>> +    rtc_fd = open(rtc_file, O_RDONLY);
>> +    if (rtc_fd < 0)
>> +        ksft_exit_fail_msg("open rtc0 failed\n");
>> +
>> +    err = ioctl(rtc_fd, RTC_RD_TIME, &alarm.time);
>> +    if (err < 0)
>> +        ksft_exit_fail_msg("get rtc time failed\n");
>> +
>> +    secs = timegm((struct tm *)&alarm.time) + 3;
>> +    gmtime_r(&secs, (struct tm *)&alarm.time);
>> +    alarm.enabled = 1;
>> +
>> +    err = ioctl(rtc_fd, RTC_WKALM_SET, &alarm);
>> +    if (err < 0)
>> +        ksft_exit_fail_msg("set wake alarm test failed, errno %d\n", 
>> errno);
> 
> Essentially with this change the test doesn't run unless
> RTC wake is supported. That sounds restrictive - is there
> another way do do this?

Hi, Shuah.

If RTC wake is a must in this testcase?

In my test, when EFI report supporting EFI_RT_SUPPORTED_SET_WAKEUP_TIME.
There will be a alarmtimer.0.auto under /sys/class/rtc/rtc0/，while 
suspending, I found alarmtimer will also been suspended and pass the 
wakeup job to RTC. When RTC calls efi_set_alarm(), this function returns 
EFI_UNSUPPORTED then suspend fails.

When EFI doesn't report supporting EFI_RT_SUPPORTED_SET_WAKEUP_TIME, 
there is no /sys/class/rtc/rtc0/alarmtimer.0.auto and alarmtimer is not 
a suspend target. Then suspend success, but never wakeup.

> 
>> +
>>       timerfd = timerfd_create(CLOCK_BOOTTIME_ALARM, 0);
>>       if (timerfd < 0)
>>           ksft_exit_fail_msg("timerfd_create() failed\n");
>> @@ -180,6 +202,7 @@ void suspend(void)
>>       if (count_after <= count_before)
>>           ksft_exit_fail_msg("Failed to enter Suspend state\n");
>> +    close(rtc_fd);
>>       close(timerfd);
>>   }
>>
> thanks,
> -- Shuah

-- 
Xinyu Zheng