msm: thermal: Update error handling of device offline

When device enters suspend, the suspend framework disables CPU hotplug
functionality. During the suspend, any attempt from KTM to hotplug CPU
will return error and in this case, KTM wont clear the cpus_offlined
mask. In this case, the device framework assumes the core is still
online. Next time the device resumes from suspend the core
online attempt will be nacked by KTM. Thus the core will be offlined and
subsequent attempts to bring the core online using device framework will
fail.

Update KTM error handling to remove the CPUs from the cpus_offlined
mask, when device offline APIs return error. Thus KTM wont block suspend
framework from bringing the core online. Also, update KTM not to
evaluate new request to offline or online a core when the device is in
suspend entry or exit. The re-evaluation will be triggered when the
device exits suspend.

Change-Id: I334fd782a2c5d604cafb94f44832d9c700891ba2
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>

diff --git a/drivers/thermal/msm_thermal.c b/drivers/thermal/msm_thermal.c
index 7158fb1..f685892 100644 (file)
--- a/drivers/thermal/msm_thermal.c
+++ b/drivers/thermal/msm_thermal.c
@@ -2931,7 +2931,7 @@ static void __ref do_core_control(int temp)
                                cpu_dev = get_cpu_device(i);
                                trace_thermal_pre_core_offline(i);
                                ret = device_offline(cpu_dev);
-                               if (ret)
+                               if (ret < 0)
                                        pr_err("Error %d offline core %d\n",
                                               ret, i);
                                trace_thermal_post_core_offline(i,
@@ -3004,7 +3004,8 @@ static int __ref update_offline_cores(int val)
                        cpu_dev = get_cpu_device(cpu);
                        trace_thermal_pre_core_offline(cpu);
                        ret = device_offline(cpu_dev);
-                       if (ret) {
+                       if (ret < 0) {
+                               cpus_offlined &= ~BIT(cpu);
                                pr_err_ratelimited(
                                        "Unable to offline CPU%d. err:%d\n",
                                        cpu, ret);
@@ -3074,6 +3075,14 @@ static __ref int do_hotplug(void *data)
                        &hotplug_notify_complete) != 0)
                        ;
                reinit_completion(&hotplug_notify_complete);
+
+               /*
+                * Suspend framework will have disabled the
+                * hotplug functionality. So wait till the suspend exits
+                * and then re-evaluate.
+                */
+               if (in_suspend)
+                       continue;
                mask = 0;
 
                mutex_lock(&core_control_mutex);