1 files changed, 161 insertions, 108 deletions

diff --git a/src/ipa/raspberrypi/controller/rpi/agc.cpp b/src/ipa/raspberrypi/controller/rpi/agc.cpp
index 52a41a55..5a282a42 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/agc.cpp
@@ -28,7 +28,7 @@ LOG_DEFINE_CATEGORY(RPiAgc)
 
 #define NAME "rpi.agc"
 
-#define PIPELINE_BITS 13 // seems to be a 13-bit pipeline
+#define PIPELINE_BITS 13 /* seems to be a 13-bit pipeline */
 
 void AgcMeteringMode::read(boost::property_tree::ptree const &params)
 {
@@ -150,7 +150,7 @@ void AgcConfig::read(boost::property_tree::ptree const &params)
 	convergenceFrames = params.get<unsigned int>("convergence_frames", 6);
 	fastReduceThreshold = params.get<double>("fast_reduce_threshold", 0.4);
 	baseEv = params.get<double>("base_ev", 1.0);
-	// Start with quite a low value as ramping up is easier than ramping down.
+	/* Start with quite a low value as ramping up is easier than ramping down. */
 	defaultExposureTime = params.get<double>("default_exposure_time", 1000) * 1us;
 	defaultAnalogueGain = params.get<double>("default_analogueGain", 1.0);
 }
@@ -170,8 +170,10 @@ Agc::Agc(Controller *controller)
 	  maxShutter_(0s), fixedShutter_(0s), fixedAnalogueGain_(0.0)
 {
 	memset(&awb_, 0, sizeof(awb_));
-	// Setting status_.totalExposureValue_ to zero initially tells us
-	// it's not been calculated yet (i.e. Process hasn't yet run).
+	/*
+	 * Setting status_.totalExposureValue_ to zero initially tells us
+	 * it's not been calculated yet (i.e. Process hasn't yet run).
+	 */
 	memset(&status_, 0, sizeof(status_));
 	status_.ev = ev_;
 }
@@ -185,16 +187,18 @@ void Agc::read(boost::property_tree::ptree const &params)
 {
 	LOG(RPiAgc, Debug) << "Agc";
 	config_.read(params);
-	// Set the config's defaults (which are the first ones it read) as our
-	// current modes, until someone changes them.  (they're all known to
-	// exist at this point)
+	/*
+	 * Set the config's defaults (which are the first ones it read) as our
+	 * current modes, until someone changes them.  (they're all known to
+	 * exist at this point)
+	 */
 	meteringModeName_ = config_.defaultMeteringMode;
 	meteringMode_ = &config_.meteringModes[meteringModeName_];
 	exposureModeName_ = config_.defaultExposureMode;
 	exposureMode_ = &config_.exposureModes[exposureModeName_];
 	constraintModeName_ = config_.defaultConstraintMode;
 	constraintMode_ = &config_.constraintModes[constraintModeName_];
-	// Set up the "last shutter/gain" values, in case AGC starts "disabled".
+	/* Set up the "last shutter/gain" values, in case AGC starts "disabled". */
 	status_.shutterTime = config_.defaultExposureTime;
 	status_.analogueGain = config_.defaultAnalogueGain;
 }
@@ -218,8 +222,10 @@ void Agc::resume()
 
 unsigned int Agc::getConvergenceFrames() const
 {
-	// If shutter and gain have been explicitly set, there is no
-	// convergence to happen, so no need to drop any frames - return zero.
+	/*
+	 * If shutter and gain have been explicitly set, there is no
+	 * convergence to happen, so no need to drop any frames - return zero.
+	 */
 	if (fixedShutter_ && fixedAnalogueGain_)
 		return 0;
 	else
@@ -244,14 +250,14 @@ void Agc::setMaxShutter(Duration maxShutter)
 void Agc::setFixedShutter(Duration fixedShutter)
 {
 	fixedShutter_ = fixedShutter;
-	// Set this in case someone calls Pause() straight after.
+	/* Set this in case someone calls Pause() straight after. */
 	status_.shutterTime = clipShutter(fixedShutter_);
 }
 
 void Agc::setFixedAnalogueGain(double fixedAnalogueGain)
 {
 	fixedAnalogueGain_ = fixedAnalogueGain;
-	// Set this in case someone calls Pause() straight after.
+	/* Set this in case someone calls Pause() straight after. */
 	status_.analogueGain = fixedAnalogueGain;
 }
 
@@ -280,30 +286,32 @@ void Agc::switchMode(CameraMode const &cameraMode,
 
 	Duration fixedShutter = clipShutter(fixedShutter_);
 	if (fixedShutter && fixedAnalogueGain_) {
-		// We're going to reset the algorithm here with these fixed values.
+		/* We're going to reset the algorithm here with these fixed values. */
 
 		fetchAwbStatus(metadata);
 		double minColourGain = std::min({ awb_.gainR, awb_.gainG, awb_.gainB, 1.0 });
 		ASSERT(minColourGain != 0.0);
 
-		// This is the equivalent of computeTargetExposure and applyDigitalGain.
+		/* This is the equivalent of computeTargetExposure and applyDigitalGain. */
 		target_.totalExposureNoDG = fixedShutter_ * fixedAnalogueGain_;
 		target_.totalExposure = target_.totalExposureNoDG / minColourGain;
 
-		// Equivalent of filterExposure. This resets any "history".
+		/* Equivalent of filterExposure. This resets any "history". */
 		filtered_ = target_;
 
-		// Equivalent of divideUpExposure.
+		/* Equivalent of divideUpExposure. */
 		filtered_.shutter = fixedShutter;
 		filtered_.analogueGain = fixedAnalogueGain_;
 	} else if (status_.totalExposureValue) {
-		// On a mode switch, various things could happen:
-		// - the exposure profile might change
-		// - a fixed exposure or gain might be set
-		// - the new mode's sensitivity might be different
-		// We cope with the last of these by scaling the target values. After
-		// that we just need to re-divide the exposure/gain according to the
-		// current exposure profile, which takes care of everything else.
+		/*
+		 * On a mode switch, various things could happen:
+		 * - the exposure profile might change
+		 * - a fixed exposure or gain might be set
+		 * - the new mode's sensitivity might be different
+		 * We cope with the last of these by scaling the target values. After
+		 * that we just need to re-divide the exposure/gain according to the
+		 * current exposure profile, which takes care of everything else.
+		 */
 
 		double ratio = lastSensitivity_ / cameraMode.sensitivity;
 		target_.totalExposureNoDG *= ratio;
@@ -313,29 +321,31 @@ void Agc::switchMode(CameraMode const &cameraMode,
 
 		divideUpExposure();
 	} else {
-		// We come through here on startup, when at least one of the shutter
-		// or gain has not been fixed. We must still write those values out so
-		// that they will be applied immediately. We supply some arbitrary defaults
-		// for any that weren't set.
-
-		// Equivalent of divideUpExposure.
+		/*
+		 * We come through here on startup, when at least one of the shutter
+		 * or gain has not been fixed. We must still write those values out so
+		 * that they will be applied immediately. We supply some arbitrary defaults
+		 * for any that weren't set.
+		 */
+
+		/* Equivalent of divideUpExposure. */
 		filtered_.shutter = fixedShutter ? fixedShutter : config_.defaultExposureTime;
 		filtered_.analogueGain = fixedAnalogueGain_ ? fixedAnalogueGain_ : config_.defaultAnalogueGain;
 	}
 
 	writeAndFinish(metadata, false);
 
-	// We must remember the sensitivity of this mode for the next SwitchMode.
+	/* We must remember the sensitivity of this mode for the next SwitchMode. */
 	lastSensitivity_ = cameraMode.sensitivity;
 }
 
 void Agc::prepare(Metadata *imageMetadata)
 {
 	status_.digitalGain = 1.0;
-	fetchAwbStatus(imageMetadata); // always fetch it so that Process knows it's been done
+	fetchAwbStatus(imageMetadata); /* always fetch it so that Process knows it's been done */
 
 	if (status_.totalExposureValue) {
-		// Process has run, so we have meaningful values.
+		/* Process has run, so we have meaningful values. */
 		DeviceStatus deviceStatus;
 		if (imageMetadata->get("device.status", deviceStatus) == 0) {
 			Duration actualExposure = deviceStatus.shutterSpeed *
@@ -343,14 +353,16 @@ void Agc::prepare(Metadata *imageMetadata)
 			if (actualExposure) {
 				status_.digitalGain = status_.totalExposureValue / actualExposure;
 				LOG(RPiAgc, Debug) << "Want total exposure " << status_.totalExposureValue;
-				// Never ask for a gain < 1.0, and also impose
-				// some upper limit. Make it customisable?
+				/*
+				 * Never ask for a gain < 1.0, and also impose
+				 * some upper limit. Make it customisable?
+				 */
 				status_.digitalGain = std::max(1.0, std::min(status_.digitalGain, 4.0));
 				LOG(RPiAgc, Debug) << "Actual exposure " << actualExposure;
 				LOG(RPiAgc, Debug) << "Use digitalGain " << status_.digitalGain;
 				LOG(RPiAgc, Debug) << "Effective exposure "
 						   << actualExposure * status_.digitalGain;
-				// Decide whether AEC/AGC has converged.
+				/* Decide whether AEC/AGC has converged. */
 				updateLockStatus(deviceStatus);
 			}
 		} else
@@ -362,44 +374,52 @@ void Agc::prepare(Metadata *imageMetadata)
 void Agc::process(StatisticsPtr &stats, Metadata *imageMetadata)
 {
 	frameCount_++;
-	// First a little bit of housekeeping, fetching up-to-date settings and
-	// configuration, that kind of thing.
+	/*
+	 * First a little bit of housekeeping, fetching up-to-date settings and
+	 * configuration, that kind of thing.
+	 */
 	housekeepConfig();
-	// Get the current exposure values for the frame that's just arrived.
+	/* Get the current exposure values for the frame that's just arrived. */
 	fetchCurrentExposure(imageMetadata);
-	// Compute the total gain we require relative to the current exposure.
+	/* Compute the total gain we require relative to the current exposure. */
 	double gain, targetY;
 	computeGain(stats.get(), imageMetadata, gain, targetY);
-	// Now compute the target (final) exposure which we think we want.
+	/* Now compute the target (final) exposure which we think we want. */
 	computeTargetExposure(gain);
-	// Some of the exposure has to be applied as digital gain, so work out
-	// what that is. This function also tells us whether it's decided to
-	// "desaturate" the image more quickly.
+	/*
+	 * Some of the exposure has to be applied as digital gain, so work out
+	 * what that is. This function also tells us whether it's decided to
+	 * "desaturate" the image more quickly.
+	 */
 	bool desaturate = applyDigitalGain(gain, targetY);
-	// The results have to be filtered so as not to change too rapidly.
+	/* The results have to be filtered so as not to change too rapidly. */
 	filterExposure(desaturate);
-	// The last thing is to divide up the exposure value into a shutter time
-	// and analogue gain, according to the current exposure mode.
+	/*
+	 * The last thing is to divide up the exposure value into a shutter time
+	 * and analogue gain, according to the current exposure mode.
+	 */
 	divideUpExposure();
-	// Finally advertise what we've done.
+	/* Finally advertise what we've done. */
 	writeAndFinish(imageMetadata, desaturate);
 }
 
 void Agc::updateLockStatus(DeviceStatus const &deviceStatus)
 {
-	const double errorFactor = 0.10; // make these customisable?
+	const double errorFactor = 0.10; /* make these customisable? */
 	const int maxLockCount = 5;
-	// Reset "lock count" when we exceed this multiple of errorFactor
+	/* Reset "lock count" when we exceed this multiple of errorFactor */
 	const double resetMargin = 1.5;
 
-	// Add 200us to the exposure time error to allow for line quantisation.
+	/* Add 200us to the exposure time error to allow for line quantisation. */
 	Duration exposureError = lastDeviceStatus_.shutterSpeed * errorFactor + 200us;
 	double gainError = lastDeviceStatus_.analogueGain * errorFactor;
 	Duration targetError = lastTargetExposure_ * errorFactor;
 
-	// Note that we don't know the exposure/gain limits of the sensor, so
-	// the values we keep requesting may be unachievable. For this reason
-	// we only insist that we're close to values in the past few frames.
+	/*
+	 * Note that we don't know the exposure/gain limits of the sensor, so
+	 * the values we keep requesting may be unachievable. For this reason
+	 * we only insist that we're close to values in the past few frames.
+	 */
 	if (deviceStatus.shutterSpeed > lastDeviceStatus_.shutterSpeed - exposureError &&
 	    deviceStatus.shutterSpeed < lastDeviceStatus_.shutterSpeed + exposureError &&
 	    deviceStatus.analogueGain > lastDeviceStatus_.analogueGain - gainError &&
@@ -430,7 +450,7 @@ static void copyString(std::string const &s, char *d, size_t size)
 
 void Agc::housekeepConfig()
 {
-	// First fetch all the up-to-date settings, so no one else has to do it.
+	/* First fetch all the up-to-date settings, so no one else has to do it. */
 	status_.ev = ev_;
 	status_.fixedShutter = clipShutter(fixedShutter_);
 	status_.fixedAnalogueGain = fixedAnalogueGain_;
@@ -438,8 +458,10 @@ void Agc::housekeepConfig()
 	LOG(RPiAgc, Debug) << "ev " << status_.ev << " fixedShutter "
 			   << status_.fixedShutter << " fixedAnalogueGain "
 			   << status_.fixedAnalogueGain;
-	// Make sure the "mode" pointers point to the up-to-date things, if
-	// they've changed.
+	/*
+	 * Make sure the "mode" pointers point to the up-to-date things, if
+	 * they've changed.
+	 */
 	if (strcmp(meteringModeName_.c_str(), status_.meteringMode)) {
 		auto it = config_.meteringModes.find(meteringModeName_);
 		if (it == config_.meteringModes.end())
@@ -491,7 +513,7 @@ void Agc::fetchCurrentExposure(Metadata *imageMetadata)
 
 void Agc::fetchAwbStatus(Metadata *imageMetadata)
 {
-	awb_.gainR = 1.0; // in case not found in metadata
+	awb_.gainR = 1.0; /* in case not found in metadata */
 	awb_.gainG = 1.0;
 	awb_.gainB = 1.0;
 	if (imageMetadata->get("awb.status", awb_) != 0)
@@ -502,8 +524,10 @@ static double computeInitialY(bcm2835_isp_stats *stats, AwbStatus const &awb,
 			      double weights[], double gain)
 {
 	bcm2835_isp_stats_region *regions = stats->agc_stats;
-	// Note how the calculation below means that equal weights give you
-	// "average" metering (i.e. all pixels equally important).
+	/*
+	 * Note how the calculation below means that equal weights give you
+	 * "average" metering (i.e. all pixels equally important).
+	 */
 	double rSum = 0, gSum = 0, bSum = 0, pixelSum = 0;
 	for (int i = 0; i < AGC_STATS_SIZE; i++) {
 		double counted = regions[i].counted;
@@ -525,11 +549,13 @@ static double computeInitialY(bcm2835_isp_stats *stats, AwbStatus const &awb,
 	return ySum / pixelSum / (1 << PIPELINE_BITS);
 }
 
-// We handle extra gain through EV by adjusting our Y targets. However, you
-// simply can't monitor histograms once they get very close to (or beyond!)
-// saturation, so we clamp the Y targets to this value. It does mean that EV
-// increases don't necessarily do quite what you might expect in certain
-// (contrived) cases.
+/*
+ * We handle extra gain through EV by adjusting our Y targets. However, you
+ * simply can't monitor histograms once they get very close to (or beyond!)
+ * saturation, so we clamp the Y targets to this value. It does mean that EV
+ * increases don't necessarily do quite what you might expect in certain
+ * (contrived) cases.
+ */
 
 #define EV_GAIN_Y_TARGET_LIMIT 0.9
 
@@ -546,18 +572,22 @@ void Agc::computeGain(bcm2835_isp_stats *statistics, Metadata *imageMetadata,
 		      double &gain, double &targetY)
 {
 	struct LuxStatus lux = {};
-	lux.lux = 400; // default lux level to 400 in case no metadata found
+	lux.lux = 400; /* default lux level to 400 in case no metadata found */
 	if (imageMetadata->get("lux.status", lux) != 0)
 		LOG(RPiAgc, Warning) << "Agc: no lux level found";
 	Histogram h(statistics->hist[0].g_hist, NUM_HISTOGRAM_BINS);
 	double evGain = status_.ev * config_.baseEv;
-	// The initial gain and target_Y come from some of the regions. After
-	// that we consider the histogram constraints.
+	/*
+	 * The initial gain and target_Y come from some of the regions. After
+	 * that we consider the histogram constraints.
+	 */
 	targetY = config_.yTarget.eval(config_.yTarget.domain().clip(lux.lux));
 	targetY = std::min(EV_GAIN_Y_TARGET_LIMIT, targetY * evGain);
 
-	// Do this calculation a few times as brightness increase can be
-	// non-linear when there are saturated regions.
+	/*
+	 * Do this calculation a few times as brightness increase can be
+	 * non-linear when there are saturated regions.
+	 */
 	gain = 1.0;
 	for (int i = 0; i < 8; i++) {
 		double initialY = computeInitialY(statistics, awb_, meteringMode_->weights, gain);
@@ -565,7 +595,7 @@ void Agc::computeGain(bcm2835_isp_stats *statistics, Metadata *imageMetadata,
 		gain *= extraGain;
 		LOG(RPiAgc, Debug) << "Initial Y " << initialY << " target " << targetY
 				   << " gives gain " << gain;
-		if (extraGain < 1.01) // close enough
+		if (extraGain < 1.01) /* close enough */
 			break;
 	}
 
@@ -592,20 +622,23 @@ void Agc::computeGain(bcm2835_isp_stats *statistics, Metadata *imageMetadata,
 void Agc::computeTargetExposure(double gain)
 {
 	if (status_.fixedShutter && status_.fixedAnalogueGain) {
-		// When ag and shutter are both fixed, we need to drive the
-		// total exposure so that we end up with a digital gain of at least
-		// 1/minColourGain. Otherwise we'd desaturate channels causing
-		// white to go cyan or magenta.
+		/*
+		 * When ag and shutter are both fixed, we need to drive the
+		 * total exposure so that we end up with a digital gain of at least
+		 * 1/minColourGain. Otherwise we'd desaturate channels causing
+		 * white to go cyan or magenta.
+		 */
 		double minColourGain = std::min({ awb_.gainR, awb_.gainG, awb_.gainB, 1.0 });
 		ASSERT(minColourGain != 0.0);
 		target_.totalExposure =
 			status_.fixedShutter * status_.fixedAnalogueGain / minColourGain;
 	} else {
-		// The statistics reflect the image without digital gain, so the final
-		// total exposure we're aiming for is:
+		/*
+		 * The statistics reflect the image without digital gain, so the final
+		 * total exposure we're aiming for is:
+		 */
 		target_.totalExposure = current_.totalExposureNoDG * gain;
-		// The final target exposure is also limited to what the exposure
-		// mode allows.
+		/* The final target exposure is also limited to what the exposure mode allows. */
 		Duration maxShutter = status_.fixedShutter
 					      ? status_.fixedShutter
 					      : exposureMode_->shutter.back();
@@ -625,17 +658,21 @@ bool Agc::applyDigitalGain(double gain, double targetY)
 	double minColourGain = std::min({ awb_.gainR, awb_.gainG, awb_.gainB, 1.0 });
 	ASSERT(minColourGain != 0.0);
 	double dg = 1.0 / minColourGain;
-	// I think this pipeline subtracts black level and rescales before we
-	// get the stats, so no need to worry about it.
+	/*
+	 * I think this pipeline subtracts black level and rescales before we
+	 * get the stats, so no need to worry about it.
+	 */
 	LOG(RPiAgc, Debug) << "after AWB, target dg " << dg << " gain " << gain
 			   << " target_Y " << targetY;
-	// Finally, if we're trying to reduce exposure but the target_Y is
-	// "close" to 1.0, then the gain computed for that constraint will be
-	// only slightly less than one, because the measured Y can never be
-	// larger than 1.0. When this happens, demand a large digital gain so
-	// that the exposure can be reduced, de-saturating the image much more
-	// quickly (and we then approach the correct value more quickly from
-	// below).
+	/*
+	 * Finally, if we're trying to reduce exposure but the target_Y is
+	 * "close" to 1.0, then the gain computed for that constraint will be
+	 * only slightly less than one, because the measured Y can never be
+	 * larger than 1.0. When this happens, demand a large digital gain so
+	 * that the exposure can be reduced, de-saturating the image much more
+	 * quickly (and we then approach the correct value more quickly from
+	 * below).
+	 */
 	bool desaturate = targetY > config_.fastReduceThreshold &&
 			  gain < sqrt(targetY);
 	if (desaturate)
@@ -649,8 +686,10 @@ bool Agc::applyDigitalGain(double gain, double targetY)
 void Agc::filterExposure(bool desaturate)
 {
 	double speed = config_.speed;
-	// AGC adapts instantly if both shutter and gain are directly specified
-	// or we're in the startup phase.
+	/*
+	 * AGC adapts instantly if both shutter and gain are directly specified
+	 * or we're in the startup phase.
+	 */
 	if ((status_.fixedShutter && status_.fixedAnalogueGain) ||
 	    frameCount_ <= config_.startupFrames)
 		speed = 1.0;
@@ -658,15 +697,19 @@ void Agc::filterExposure(bool desaturate)
 		filtered_.totalExposure = target_.totalExposure;
 		filtered_.totalExposureNoDG = target_.totalExposureNoDG;
 	} else {
-		// If close to the result go faster, to save making so many
-		// micro-adjustments on the way. (Make this customisable?)
+		/*
+		 * If close to the result go faster, to save making so many
+		 * micro-adjustments on the way. (Make this customisable?)
+		 */
 		if (filtered_.totalExposure < 1.2 * target_.totalExposure &&
 		    filtered_.totalExposure > 0.8 * target_.totalExposure)
 			speed = sqrt(speed);
 		filtered_.totalExposure = speed * target_.totalExposure +
 					  filtered_.totalExposure * (1.0 - speed);
-		// When desaturing, take a big jump down in totalExposureNoDG,
-		// which we'll hide with digital gain.
+		/*
+		 * When desaturing, take a big jump down in totalExposureNoDG,
+		 * which we'll hide with digital gain.
+		 */
 		if (desaturate)
 			filtered_.totalExposureNoDG =
 				target_.totalExposureNoDG;
@@ -675,9 +718,11 @@ void Agc::filterExposure(bool desaturate)
 				speed * target_.totalExposureNoDG +
 				filtered_.totalExposureNoDG * (1.0 - speed);
 	}
-	// We can't let the totalExposureNoDG exposure deviate too far below the
-	// total exposure, as there might not be enough digital gain available
-	// in the ISP to hide it (which will cause nasty oscillation).
+	/*
+	 * We can't let the totalExposureNoDG exposure deviate too far below the
+	 * total exposure, as there might not be enough digital gain available
+	 * in the ISP to hide it (which will cause nasty oscillation).
+	 */
 	if (filtered_.totalExposureNoDG <
 	    filtered_.totalExposure * config_.fastReduceThreshold)
 		filtered_.totalExposureNoDG = filtered_.totalExposure * config_.fastReduceThreshold;
@@ -687,9 +732,11 @@ void Agc::filterExposure(bool desaturate)
 
 void Agc::divideUpExposure()
 {
-	// Sending the fixed shutter/gain cases through the same code may seem
-	// unnecessary, but it will make more sense when extend this to cover
-	// variable aperture.
+	/*
+	 * Sending the fixed shutter/gain cases through the same code may seem
+	 * unnecessary, but it will make more sense when extend this to cover
+	 * variable aperture.
+	 */
 	Duration exposureValue = filtered_.totalExposureNoDG;
 	Duration shutterTime;
 	double analogueGain;
@@ -721,18 +768,22 @@ void Agc::divideUpExposure()
 	}
 	LOG(RPiAgc, Debug) << "Divided up shutter and gain are " << shutterTime << " and "
 			   << analogueGain;
-	// Finally adjust shutter time for flicker avoidance (require both
-	// shutter and gain not to be fixed).
+	/*
+	 * Finally adjust shutter time for flicker avoidance (require both
+	 * shutter and gain not to be fixed).
+	 */
 	if (!status_.fixedShutter && !status_.fixedAnalogueGain &&
 	    status_.flickerPeriod) {
 		int flickerPeriods = shutterTime / status_.flickerPeriod;
 		if (flickerPeriods) {
 			Duration newShutterTime = flickerPeriods * status_.flickerPeriod;
 			analogueGain *= shutterTime / newShutterTime;
-			// We should still not allow the ag to go over the
-			// largest value in the exposure mode. Note that this
-			// may force more of the total exposure into the digital
-			// gain as a side-effect.
+			/*
+			 * We should still not allow the ag to go over the
+			 * largest value in the exposure mode. Note that this
+			 * may force more of the total exposure into the digital
+			 * gain as a side-effect.
+			 */
 			analogueGain = std::min(analogueGain, exposureMode_->gain.back());
 			shutterTime = newShutterTime;
 		}
@@ -749,8 +800,10 @@ void Agc::writeAndFinish(Metadata *imageMetadata, bool desaturate)
 	status_.targetExposureValue = desaturate ? 0s : target_.totalExposureNoDG;
 	status_.shutterTime = filtered_.shutter;
 	status_.analogueGain = filtered_.analogueGain;
-	// Write to metadata as well, in case anyone wants to update the camera
-	// immediately.
+	/*
+	 * Write to metadata as well, in case anyone wants to update the camera
+	 * immediately.
+	 */
 	imageMetadata->set("agc.status", status_);
 	LOG(RPiAgc, Debug) << "Output written, total exposure requested is "
 			   << filtered_.totalExposure;
@@ -765,7 +818,7 @@ Duration Agc::clipShutter(Duration shutter)
 	return shutter;
 }
 
-// Register algorithm with the system.
+/* Register algorithm with the system. */
 static Algorithm *create(Controller *controller)
 {
 	return (Algorithm *)new Agc(controller);