Changed how we update extrusion accumulators, fixed poss. race condition

3 files changed, 50 insertions, 12 deletions

diff --git a/src/Movement/DDA.cpp b/src/Movement/DDA.cpp
index 69626146..cf95272d 100644
--- a/src/Movement/DDA.cpp
+++ b/src/Movement/DDA.cpp
@@ -2326,6 +2326,50 @@ void DDA::LimitSpeedAndAcceleration(float maxSpeed, float maxAcceleration) noexc
 	}
 }
 
+// Update the movement accumulators to account for the move that has just finished.
+// Only drives that correspond to extruders need to be updated, but it doesn't matter if we update them all.
+// This is called with interrupts disabled.
+void DDA::UpdateMovementAccumulators(volatile int32_t *accumulators) const noexcept
+{
+	// To identify all the extruder movement, we can either loop through extruder numbers and search both DM lists for a DM for that drive,
+	// or we can iterate through both DM lists, checking whether the drive it is for is an extruder.
+#if 1
+	// Loop through DMs, checking whether each associated drive is an extruder and updating the movement accumulator if so.
+	// We could omit the check that the drive is an accumulator so that we update all accumulators, but we would still need to check for leadscrew adjustment moves.
+	const unsigned int firstExtruderDrive = ExtruderToLogicalDrive(reprap.GetGCodes().GetNumExtruders() - 1);
+	for (const DriveMovement* dm = activeDMs; dm != nullptr; )
+	{
+		const uint8_t drv = dm->drive;
+		if (   drv >= firstExtruderDrive						// check that it's an extruder (to save the call to GetStepsTaken)
+			&& drv < MaxAxesPlusExtruders						// check that it's not a direct leadscrew move
+		   )
+		{
+			accumulators[drv] += dm->GetNetStepsTaken();
+		}
+		dm = dm->nextDM;
+	}
+	for (const DriveMovement* dm = completedDMs; dm != nullptr; )
+	{
+		const uint8_t drv = dm->drive;
+		if (   drv >= firstExtruderDrive						// check that it's an extruder (to save the call to GetStepsTaken)
+			&& drv < MaxAxesPlusExtruders						// check that it's not a direct leadscrew move
+		   )
+		{
+			accumulators[drv] += dm->GetNetStepsTaken();
+		}
+		dm = dm->nextDM;
+	}
+#else
+	// Loop through extruders
+	const size_t numExtruders = reprap.GetGCodes().GetNumExtruders();
+	for (size_t extruder = 0; extruder < numExtruders; ++extruder)
+	{
+		const size_t drv = ExtruderToLogicalDrive(extruder);
+		accumulators[drv] += GetStepsTaken(drv);
+	}
+#endif
+}
+
 #if SUPPORT_LASER
 
 // Manage the laser power. Return the number of ticks until we should be called again, or 0 to be called at the start of the next move.
diff --git a/src/Movement/DDA.h b/src/Movement/DDA.h
index 2c693d98..035b8f42 100644
--- a/src/Movement/DDA.h
+++ b/src/Movement/DDA.h
@@ -160,6 +160,7 @@ public:
 	uint32_t GetClocksNeeded() const noexcept { return clocksNeeded; }
 	bool IsGoodToPrepare() const noexcept;
 	bool IsNonPrintingExtruderMove() const noexcept { return flags.isNonPrintingExtruderMove; }
+	void UpdateMovementAccumulators(volatile int32_t *accumulators) const noexcept;
 
 #if SUPPORT_LASER || SUPPORT_IOBITS
 	LaserPwmOrIoBits GetLaserPwmOrIoBits() const noexcept { return laserPwmOrIoBits; }
diff --git a/src/Movement/DDARing.cpp b/src/Movement/DDARing.cpp
index 23270b35..4aeb39a7 100644
--- a/src/Movement/DDARing.cpp
+++ b/src/Movement/DDARing.cpp
@@ -572,18 +572,12 @@ void DDARing::CurrentMoveCompleted() noexcept
 	liveCoordinatesValid = cdda->FetchEndPosition(const_cast<int32_t*>(liveEndPoints), const_cast<float *>(liveCoordinates));
 	liveCoordinatesChanged = true;
 
-	// In the following it doesn't currently matter whether we process all drives or just the extruders
-	// Instead of looping through extruders, we could loop through DMs.
+	// Disable interrupts before we touch any extrusion accumulators until after we set currentDda to null, in case the filament monitor interrupt has higher priority than ours
 	{
-		const size_t numExtruders = reprap.GetGCodes().GetNumExtruders();
-		for (size_t extruder = 0; extruder < numExtruders; ++extruder)
-		{
-			const size_t drv = ExtruderToLogicalDrive(extruder);
-			movementAccumulators[drv] += cdda->GetStepsTaken(drv);
-		}
+		AtomicCriticalSectionLocker lock;
+		cdda->UpdateMovementAccumulators(movementAccumulators);
+		currentDda = nullptr;
 	}
-
-	currentDda = nullptr;
 	if (cdda->IsCheckingEndstops())
 	{
 		Move::WakeMoveTaskFromISR();				// wake the Move task if we were checking endstops
@@ -607,13 +601,12 @@ bool DDARing::SetWaitingToEmpty() noexcept
 
 int32_t DDARing::GetAccumulatedMovement(size_t drive, bool& isPrinting) noexcept
 {
-	const uint32_t basepri = ChangeBasePriority(NvicPriorityStep);
+	AtomicCriticalSectionLocker lock;
 	const int32_t ret = movementAccumulators[drive];
 	const DDA * const cdda = currentDda;						// capture volatile variable
 	const int32_t adjustment = (cdda == nullptr) ? 0 : cdda->GetStepsTaken(drive);
 	movementAccumulators[drive] = -adjustment;
 	isPrinting = extrudersPrinting;
-	RestoreBasePriority(basepri);
 	return ret + adjustment;
 }