> On Sep 23, 2024, at 2:46 PM, Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On 9/23/24 15:18, Yifei Liu wrote:
>>> On Sep 23, 2024, at 1:56 PM, Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> wrote:
>>>
>>> On 9/23/24 14:47, Yifei Liu wrote:
>>>> We recently notice that the step_after_suspend_test would
>>>
>>> noticed
>> How about change this to find?
>
> Either is fine - it would found instead of find - or you could write
> it as below:
>
> "step_after_suspend_test fails with device busy error while
> writing to /sys/power/state to start suspend.”
Thanks
>
>>>
>>>> fail on our plenty devices. The test believesit failed to
>>>
>>> "several of our devices" believes it
>>>> enter suspend state with
>>>
>>> Please do fix the above as pointed out earlier on v1.
>> Apologies, forget to fix. Will fix that.
>>>> $ sudo ./step_after_suspend_test
>>>> TAP version 13
>>>> Bail out! Failed to enter Suspend state
>>>> However, in the kernel message, I indeed see the system get
>>>> suspended and then wake up later.
>>>> [611172.033108] PM: suspend entry (s2idle)
>>>> [611172.044940] Filesystems sync: 0.006 seconds
>>>> [611172.052254] Freezing user space processes
>>>> [611172.059319] Freezing user space processes completed (elapsed 0.001 seconds)
>>>> [611172.067920] OOM killer disabled.
>>>> [611172.072465] Freezing remaining freezable tasks
>>>> [611172.080332] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
>>>> [611172.089724] printk: Suspending console(s) (use no_console_suspend to debug)
>>>> [611172.117126] serial 00:03: disabled
>>>> --- some other hardware get reconnected ---
>>>> [611203.136277] OOM killer enabled.
>>>> [611203.140637] Restarting tasks ...
>>>> [611203.141135] usb 1-8.1: USB disconnect, device number 7
>>>> [611203.141755] done.
>>>> [611203.155268] random: crng reseeded on system resumption
>>>> [611203.162059] PM: suspend exit
>>>> After investigation, I notice that for the code block
>>>
>>> noticed?
>> How about use find here?
>
> It is the tense issue - found or noticed would work.
Thanks
>>>
>>>> if (write(power_state_fd, "mem", strlen("mem")) != strlen("mem"))
>>>> ksft_exit_fail_msg("Failed to enter Suspend state\n");
>>>> The write will return -1 and errno is set to 16 (device busy).
>>>> It should be caused by the write function is not successfully returned
>>>> before the system suspend and the return value get messed when waking up.
>>>> As a result, It may be better to check the time passed of those few instructions
>>>> to determine whether the suspend is executed correctly for it is pretty hard to
>>>> execute those few lines for 5 seconds.
>>>> The timer to wake up the system is set to expired after 5 seconds and no-rearm.
>>>> If the timer remaining time is 0 second and 0 nano secomd, it means the timer
>>>> expired and wake the system up. Otherwise, the system could be considered to
>>>> enter the suspend state failed if there is any remaining time.
>>>
>>> What would you get if you were to cat /sys/power/state at this point?
>> According to file kernel/power/suspend, the cat will always return freeze mem disk.
>>> Does this fix the problem you are seeing? What is the outcome?
>> Yes, it fixes. The test would not fail for it believes the system does not went to suspend by mistake. It now could continue to the rest part of the test after suspend.
>
> Can you add this to the change log.
Sure. I will send a v3 later.
>
>>>> Fixes: bfd092b8c2728 ("selftests: breakpoint: add step_after_suspend_test")
>>>> Reported-by: Sinadin Shan <sinadin.shan@xxxxxxxxxx>
>>>> Signed-off-by: Yifei Liu <yifei.l.liu@xxxxxxxxxx>
>>>> ---
>>>> .../testing/selftests/breakpoints/step_after_suspend_test.c | 5 ++++-
>>>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>>> diff --git a/tools/testing/selftests/breakpoints/step_after_suspend_test.c b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
>>>> index dfec31fb9b30d..33f5542bf741d 100644
>>>> --- a/tools/testing/selftests/breakpoints/step_after_suspend_test.c
>>>> +++ b/tools/testing/selftests/breakpoints/step_after_suspend_test.c
>>>> @@ -152,7 +152,10 @@ void suspend(void)
>>>> if (err < 0)
>>>> ksft_exit_fail_msg("timerfd_settime() failed\n");
>>>> - if (write(power_state_fd, "mem", strlen("mem")) != strlen("mem"))
>>>> + system("(echo mem > /sys/power/state) 2> /dev/null");
>>>> +
>>>> + timerfd_gettime(timerfd,&spec);
>>>> + if (spec.it_value.tv_sec != 0 || spec.it_value.tv_nsec != 0)
>>>> ksft_exit_fail_msg("Failed to enter Suspend state\n");
>>>> close(timerfd);
>>>
>
> thanks,
> — Shuah
Yifei
