SRV_Channel: fix override timeout without repeated calls

libraries/SRV_Channel/SRV_Channel.cpp

@@ -113,6 +113,8 @@ uint16_t SRV_Channel::pwm_from_angle(int16_t scaled_value) const
 void SRV_Channel::calc_pwm(int16_t output_scaled)
 {
     if (have_pwm_mask & (1U<<ch_num)) {
+        // Note that this allows a set_output_pwm call to override E-Stop!!
+        // tricky to fix because we would endup E-stoping to individual SEROVx_MIN not MOT_PWM_MIN on copter
         return;
     }
 
@@ -123,13 +125,16 @@ void SRV_Channel::calc_pwm(int16_t output_scaled)
         force = true;
     }
 
-    uint16_t pwm;
+    if (!force && override_active) {
+        // don't overwrite a override
+        return;
+    }
+
     if (type_angle) {
-        pwm = pwm_from_angle(output_scaled);
+        output_pwm = pwm_from_angle(output_scaled);
     } else {
-        pwm = pwm_from_range(output_scaled);
+        output_pwm = pwm_from_range(output_scaled);
     }
-    set_output_pwm(pwm,force);
 }
 
 void SRV_Channel::set_output_pwm(uint16_t pwm, bool force)

libraries/SRV_Channel/SRV_Channels.cpp

@@ -328,7 +328,16 @@ void SRV_Channels::set_output_pwm_chan_timeout(uint8_t chan, uint16_t value, uin
         const uint32_t loop_count = ((timeout_ms * 1000U) + (loop_period_us - 1U)) / loop_period_us;
         override_counter[chan] = constrain_int32(loop_count, 0, UINT16_MAX);
         channels[chan].set_override(true);
+        const bool had_pwm = SRV_Channel::have_pwm_mask & (1U<<chan);
         channels[chan].set_output_pwm(value,true);
+        if (!had_pwm) {
+            // clear the have PWM mask so the channel will default back to the scaled value when timeout expires
+            // this is also cleared by set_output_scaled but that requires it to be re-called as some point
+            // after the timeout is applied
+            // note that we can't default back to a pre-override PWM value as it is not stored
+            // checking had_pwm means the PWM will not change after the timeout, this was the existing behaviour
+            SRV_Channel::have_pwm_mask &= ~(1U<<chan);
+        }
     }
 }