Re: [PATCH v2 03/28] coresight: etm3x: Always set tracer's device mode on target CPU

On Wed, Jul 02, 2025 at 11:18:21AM +0100, Yeoreum Yun wrote:

Hi Leo,

[...]

...

@@ -464,17 +477,29 @@ static int etm_enable_perf(struct coresight_device *csdev, struct perf_event *event, struct coresight_path *path) {

• int ret = 0; struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

• if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))

• return -EINVAL;
  

• if (!coresight_take_mode(csdev, CS_MODE_PERF))

• return -EBUSY;
  

• if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id())) {

• ret = -EINVAL;
  

• goto out;
  

• }

Small question: why drvdata->cpu != smp_processor_id() check after changing mode? Would it better to check before change of it?

You are right. I will update in next version.

Thanks for pointing out this!

Leo