Re: [PATCH v3 16/31] coresight: Add callback to determine if context save/restore is needed

On Wed, Oct 01, 2025 at 11:36:07AM +0100, Mike Leach wrote:

[...]

...

+static bool coresight_need_save_restore_source(struct coresight_device *csdev) +{

•   if (!csdev)
  

•           return false;
  

•   if (source_ops(csdev)->need_context_save_restore)
  

check the actual save and restore ops here too?

Will do.

...

•           return source_ops(csdev)->need_context_save_restore(csdev);
  

•   if (coresight_get_mode(csdev))
  

•           return true;
  

Not needed - should decide only on the previous need_context_save_restore() test. Components such as STM, ETR, ETB all use the mode status, but may not support / need save and restore.

Checking mode here is for ETMv3, which no need_context_save_restore() callback.

Note, STM is a system wise component (unlike ETM is CPU-wise component), thus it is irrelevant to CPU power management.

[...]

...

static const struct coresight_ops_source etm4_source_ops = {

•   .cpu_id         = etm4_cpu_id,
  

•   .enable         = etm4_enable,
  

•   .disable        = etm4_disable,
  

•   .resume_perf    = etm4_resume_perf,
  

•   .pause_perf     = etm4_pause_perf,
  

•   .save           = etm4_cpu_save,
  

•   .restore        = etm4_cpu_restore,
  

•   .cpu_id                    = etm4_cpu_id,
  

•   .enable                    = etm4_enable,
  

•   .disable                   = etm4_disable,
  

•   .resume_perf               = etm4_resume_perf,
  

•   .pause_perf                = etm4_pause_perf,
  

•   .save                      = etm4_cpu_save,
  

•   .restore                   = etm4_cpu_restore,
  

Above are just white space change noise as far as I can see.

Will drop in next spin.

Thanks, Leo