Re: [PATCH v5 09/11] coresight: etm4x: Add flag to control single-shot restart

[Leo Yan <leo.yan@arm.com>]

On Tue, Nov 11, 2025 at 09:43:13AM +0000, Suzuki Kuruppassery Poulose wrote:

[...]

> >    if (!is_idle_task(current)) {
> >        if (config->ss_ctrl[i] || config->ss_pe_cmp[i])
> >            config->ss_status[i] &= ~TRCSSCSRn_STATUS;
> >    }
> 
> What happens when we do a system wide session and a CPU is running an
> idle task ?

For a system wide trace, the ETM device is enabled and disabled by
the perf when the session start and finish.

During the session:

- If CPU off states are not enabled, nothing will happen in idle
  threads, as no CPU PM notifier will be invoked.

- If CPU off states have been enabled, CPU PM notifier will save and
  restore ETM device context, and keep single-shot status.  This is
  same with current save/restore flow.

I don't see any issue for this.

Thanks,
Leo