[libcamera-devel,[PATCH,v4.1,4/4] ipa: ipu3: awb: Clamp gain values
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Message ID 20220311133705.511853-1-umang.jain@ideasonboard.com
State Accepted
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Series
  • [libcamera-devel] ipa: ipu3: awb: Clamp gain values
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Commit Message

Umang Jain March 11, 2022, 1:37 p.m. UTC 
From: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>

The gain values are coded as u3.13 fixed point values, ie they can not
be more than 8. Clamp the values in order to avoid any off limits value
which could make the IPU3 behave in a weird manner.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
---
 src/ipa/ipu3/algorithms/awb.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

Patch
diff mbox series 

diff --git a/src/ipa/ipu3/algorithms/awb.cpp b/src/ipa/ipu3/algorithms/awb.cpp
index 1dc27fc9..87a6cc7a 100644
--- a/src/ipa/ipu3/algorithms/awb.cpp
+++ b/src/ipa/ipu3/algorithms/awb.cpp
@@ -353,6 +353,14 @@  void Awb::awbGreyWorld()
 
 	/* Color temperature is not relevant in Grey world but still useful to estimate it :-) */
 	asyncResults_.temperatureK = estimateCCT(sumRed.R, sumRed.G, sumBlue.B);
+
+	/*
+	 * Gain values are unsigned integer value ranging [0, 8) with 13 bit
+	 * fractional part.
+	 */
+	redGain = std::clamp(redGain, 0.0, 65535.0 / 8192);
+	blueGain = std::clamp(blueGain, 0.0, 65535.0 / 8192);
+
 	asyncResults_.redGain = redGain;
 	/* Hardcode the green gain to 1.0. */
 	asyncResults_.greenGain = 1.0;