[libcamera-devel] [PATCH v1 5/6] ipa: rpi: agc: Fetch AWB status in the prepare method

[Naushir Patuck]

From: David Plowman <david.plowman at raspberrypi.com>

AWB writes this out during prepare, so we may as well read it in AGC
prepare as well. Reading it in process is wrong on the PiSP platform
because process runs before prepare, so the AWB status won't be there
(on vc4 it made no difference).

Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
Reviewed-by: Naushir Patuck <naush at raspberrypi.com>
---
 src/ipa/rpi/controller/rpi/agc_channel.cpp | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/ipa/rpi/controller/rpi/agc_channel.cpp b/src/ipa/rpi/controller/rpi/agc_channel.cpp
index 3efb6482b67f..8d374b53689d 100644
--- a/src/ipa/rpi/controller/rpi/agc_channel.cpp
+++ b/src/ipa/rpi/controller/rpi/agc_channel.cpp
@@ -270,7 +270,11 @@ AgcChannel::AgcChannel()
 	  lastTargetExposure_(0s), ev_(1.0), flickerPeriod_(0s),
 	  maxShutter_(0s), fixedShutter_(0s), fixedAnalogueGain_(0.0)
 {
-	memset(&awb_, 0, sizeof(awb_));
+	/* Set AWB default values in case early frames have no updates in metadata. */
+	awb_.gainR = 1.0;
+	awb_.gainG = 1.0;
+	awb_.gainB = 1.0;
+
 	/*
 	 * Setting status_.totalExposureValue_ to zero initially tells us
 	 * it's not been calculated yet (i.e. Process hasn't yet run).
@@ -409,7 +413,6 @@ void AgcChannel::switchMode(CameraMode const &cameraMode,
 	Duration fixedShutter = limitShutter(fixedShutter_);
 	if (fixedShutter && fixedAnalogueGain_) {
 		/* 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);
@@ -464,6 +467,9 @@ void AgcChannel::prepare(Metadata *imageMetadata)
 	AgcStatus delayedStatus;
 	AgcPrepareStatus prepareStatus;
 
+	/* Fetch the AWB status now because AWB also sets it in the prepare method. */
+	fetchAwbStatus(imageMetadata);
+
 	if (!imageMetadata->get("agc.delayed_status", delayedStatus))
 		totalExposureValue = delayedStatus.totalExposureValue;
 
@@ -507,8 +513,6 @@ void AgcChannel::process(StatisticsPtr &stats, DeviceStatus const &deviceStatus,
 	 * configuration, that kind of thing.
 	 */
 	housekeepConfig();
-	/* Fetch the AWB status immediately, so that we can assume it's there. */
-	fetchAwbStatus(imageMetadata);
 	/* Get the current exposure values for the frame that's just arrived. */
 	fetchCurrentExposure(deviceStatus);
 	/* Compute the total gain we require relative to the current exposure. */
@@ -637,9 +641,6 @@ void AgcChannel::fetchCurrentExposure(DeviceStatus const &deviceStatus)
 
 void AgcChannel::fetchAwbStatus(Metadata *imageMetadata)
 {
-	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)
 		LOG(RPiAgc, Debug) << "No AWB status found";
 }
-- 
2.34.1