ipa: raspberrypi: agc: Fix digital gain calculation for manual mode

The digital gain calculation uses a total exposure value computed with the
current AGC state. However, this is wrong in the case of manual shutter/gain
controls, as the total exposure value used must be the value computed when the
AGC sent the manual shutter/gain controls to the pipeline handler to action.

To fix this, the IPA now adds the historical AgcStatus structure to the metadata
(tagged with "agc.delayed_status"). This historical AgcStatus structure contains
the total exposure value calculated when the AGC sent the manual shutter/gain
controls to the pipeline handler.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Tested-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
index 3157805c..0f914f84 100644
--- a/src/ipa/raspberrypi/raspberrypi.cpp
+++ b/src/ipa/raspberrypi/raspberrypi.cpp
@@ -1031,6 +1031,17 @@ void IPARPi::prepareISP(const ISPConfig &data)
 	}
 
 	/*
+	 * AGC wants to know the algorithm status from the time it actioned the
+	 * sensor exposure/gain changes. So fetch it from the metadata list
+	 * indexed by the IPA cookie returned, and put it in the current frame
+	 * metadata.
+	 */
+	AgcStatus agcStatus;
+	RPiController::Metadata &delayedMetadata = rpiMetadata_[data.delayContext];
+	if (!delayedMetadata.get<AgcStatus>("agc.status", agcStatus))
+		rpiMetadata.set("agc.delayed_status", agcStatus);
+
+	/*
 	 * This may overwrite the DeviceStatus using values from the sensor
 	 * metadata, and may also do additional custom processing.
 	 */