The relative luminance is calculated using an iterative process to
account for saturation in the sensor, as multiplying pixels by a gain
doesn't increase the relative luminance by the same factor if some
regions are saturated. Relative luminance estimation doesn't apply a
saturation, which produces a value that doesn't match what the sensor
will output, and defeats the point of the iterative process. Fix it.
Fixes: f8f07f9468 ("ipa: ipu3: agc: Improve gain calculation")
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>