Re: [PATCH v3] cpuidle: psci: Add trace for PSCI domain idle

[Kevin Hilman <khilman@kernel.org>]

Keita Morisaki <keyz@google.com> writes:

> The trace event cpu_idle provides insufficient information for debugging
> PSCI requests due to lacking access to determined PSCI domain idle
> states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
> idle states the power domain has.
>
> Add new trace events namely psci_domain_idle_enter and
> psci_domain_idle_exit to trace enter and exit events with a determined
> idle state.
>
> These new trace events will help developers debug CPUidle issues on ARM
> systems using PSCI by providing more detailed information about the
> requested idle states.
>
> Signed-off-by: Keita Morisaki <keyz@google.com>
> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Tested-by: Kevin Hilman <khilman@baylibre.com>

I've been using some local trace_printk() to do exactly this, so I fully
support having some official tracepoints here. 

For my local hacks, I was trackin the state index as well as the state
value since for quick debug, I find the index to more human readable
than the state value, which I have to compare with the
arm,psci-suspend-pararm from the DT.

Anyways, thanks for submitting this!

Kevin