On 17/02/17 07:28, Chunyan Zhang wrote:

Hi Sudeep,

On ?,  2? 14, 2017 at 04:44:53?? +0000, Sudeep Holla wrote:

quoted

On Tue, Feb 14, 2017 at 9:19 AM, Chunyan Zhang
[off-list ref] wrote:

[..]

quoted

quoted

+       idle-states{
+               entry-method = "arm,psci";
+
+               CORE_PD: core_pd {
+                       compatible = "arm,idle-state";
+                       entry-latency-us = <1000>;
+                       exit-latency-us = <700>;
+                       min-residency-us = <2500>;
+                       local-timer-stop;
+                       arm,psci-suspend-param = <0x00010002>;
+               };
+
+               CLUSTER_PD: cluster_pd {
+                       compatible = "arm,idle-state";
+                       entry-latency-us = <1000>;
+                       exit-latency-us = <1000>;
+                       min-residency-us = <3000>;
+                       local-timer-stop;
+                       arm,psci-suspend-param = <0x01010003>;
+               };
+
+               DEEP_SLEEP: deep_sleep {
+                       compatible = "arm,idle-state";
+                       wakeup-latency-us = <0xffffffff>;

A value > 4294 seconds(i.e >1 hour) seems suspicious.
Are you working around the firmware issue with high latency value so
that it's never entered ? Why not remove advertising the state from DT.

Haved checked with related colleagues, this node 'deep_sleep' was not for working
around any firmware issue, but was a trick utilization of idle subsystem, and that

Really ? Any latency greater few milliseconds are sounds useless. I
still don't understand what you mean by "trick utilization of idle
subsystem".

was definitely not elegant, the author indeed intendly didn't want CPU entered this
state, I will remove this node therefore.

It's quick and dirty "HACK* to retain and advertise the state but
ensure it's never entered and obstruct the boot. It's not a trick to
exploit any idle subsystem utilization.

quoted

Can you get me the dump of:
grep "" /sys/devices/system/cpu/cpu*/cpuidle/state*/{time,usage}

FYI: https://www.irccloud.com/pastebin/XyEMLzfq/

As expected, state3(deep_sleep) is never entered.

-- 
Regards,
Sudeep