From d653499efc8eec672d23991c4dae6fa35f430a4f Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Tue, 7 Jun 2022 19:39:50 +1000
Subject: [PATCH] AP_InertialSensor: count filters to match notch options

this allows for much more complex filter setups as long as not
filtering on all IMUs
---
 libraries/AP_InertialSensor/AP_InertialSensor.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_InertialSensor/AP_InertialSensor.cpp b/libraries/AP_InertialSensor/AP_InertialSensor.cpp
index b0731fd4bb..6e9f61f809 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor.cpp
@@ -930,9 +930,10 @@ AP_InertialSensor::init(uint16_t loop_rate)
         // calculate number of notches we might want to use for harmonic notch
         if (notch.params.enabled() || fft_enabled) {
             const bool double_notch = notch.params.hasOption(HarmonicNotchFilterParams::Options::DoubleNotch);
+            const bool all_sensors = notch.params.hasOption(HarmonicNotchFilterParams::Options::EnableOnAllIMUs);
             num_filters += __builtin_popcount(notch.params.harmonics())
                 * notch.num_dynamic_notches * (double_notch ? 2 : 1)
-                * sensors_used;
+                * (all_sensors?sensors_used:1);
         }
     }