Allow to disable offlining of non-boot CPUs

On my Cherrytrail tablet I've been trying to achieve the S0Ix deep sleep
states. After a bit of twiddling I found out that I can achieve the deep
sleep states but I need to disable the power off of the secondary cores
otherwise the resume from sleep causes the device to crash.

The patch uses a property to determine whether to power off the non-boot
CPUs on sleeping.

diff --git a/power.c b/power.c
index cd284d5..7d2a4ac 100644 (file)
--- a/power.c
+++ b/power.c
@@ -74,7 +74,9 @@ static void power_set_interactive(struct power_module *module UNUSED, int on)
         }
     }
 
-    set_nonboot_cpu_state(on ? CPU_ONLINE : CPU_OFFLINE);
+    if (property_get_bool("power.nonboot-cpu-off", 1)) {
+        set_nonboot_cpu_state(on ? CPU_ONLINE : CPU_OFFLINE);
+    }
 }
 
 static void power_hint(struct power_module *module UNUSED, power_hint_t hint, void *data UNUSED)