Disable cached PWM writes in tlBMC Thermal Control

Google-Bug-Id:545704112
PiperOrigin-RevId: 978114615
Change-Id: I72b8f66ccfe550a744bb7806dc003c509161d910

tlbmc/collector/thermal_collector.cc

diff --git a/tlbmc/collector/thermal_collector.cc b/tlbmc/collector/thermal_collector.cc
index a55e2d4..a3af7d3 100644
--- a/tlbmc/collector/thermal_collector.cc
+++ b/tlbmc/collector/thermal_collector.cc
@@ -1335,10 +1335,9 @@
           ApplyPendingTuningRequests(zone_manager->GetId());
         }
 
-        // Under manual mode, perform no thermal loop iterations.
+        // Under manual mode, simply trigger the next thermal control iteration,
+        // and then return, without executing the thermal and fan cycles.
         if (zone_manager->GetManualMode()) {
-          // Write cached PWM to fans to avoid triggering hardware failsafe.
-          zone_manager->WriteCurrentPwmToFans();
           ProcessThermalControl(zone_manager, timer, /*first_run=*/false,
                                 ms_elapsed_in_current_cycle);
           return;

tlbmc/thermal/zone_manager.cc

diff --git a/tlbmc/thermal/zone_manager.cc b/tlbmc/thermal/zone_manager.cc
index 798fd57..f61cf35 100644
--- a/tlbmc/thermal/zone_manager.cc
+++ b/tlbmc/thermal/zone_manager.cc
@@ -596,15 +596,6 @@
 
 void ZoneManager::WriteCurrentPwmToFans() {
   for (const std::string& fan_name : GetFanNames()) {
-    {
-      absl::MutexLock lock(mutex_);
-      auto it = fan_name_to_manual_pwm_.find(fan_name);
-      if (it != fan_name_to_manual_pwm_.end()) {
-        WriteFanSpeed(fan_name, it->second);
-        continue;
-      }
-    }
-
     std::shared_ptr<const Sensor> pwm_sensor =
         aggregator_->GetSensorBySensorKey(fan_name);
     if (pwm_sensor == nullptr || pwm_sensor->GetSensorData() == nullptr ||