[PATCH v3 10/31] coresight: etm4x: Reuse normal enable and disable logic in CPU idle

[Leo Yan]

On Wed, Oct 01, 2025 at 01:15:01PM +0100, Mike Leach wrote:

[...]

> If the firmware is PSCI compliant there is no need to save/restore the
> context within the kernel driver if the external claim bit is set?

Yes, this is my conclusion.

A strong reason is that an external debugger should work even without
the ETM driver.

In the current implementation [1], the ETMv4 driver saves and restores
the claim bit only in sysfs or perf modes, which means it does not
serve the case where an external debugger has already claimed the
device.

Thanks,
Leo

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/hwtracing/coresight/coresight-etm4x-core.c#n1940