[PATCH] libcamera: software_isp: Reset stored exposure in black level

[Milan Zamazal]

Automatic black level setting in software ISP updates the determined
black level value when exposure or gain change.  It stores the last
exposure and gain values to detect the change.

BlackLevel::configure() resets the stored black level value but not the
exposure and gain values.  This can prevent updating the black value and
cause bad image output e.g. after suspending and resuming a camera, if
exposure and gain remain unchanged.

Let's reset the stored exposure and gain values in
BlackLevel::configure() to fix the problem.

Bug: https://bugs.libcamera.org/show_bug.cgi?id=259
Signed-off-by: Milan Zamazal <mzamazal at redhat.com>
---
 src/ipa/simple/algorithms/blc.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/ipa/simple/algorithms/blc.cpp b/src/ipa/simple/algorithms/blc.cpp
index 1d7d370b..14cf31bf 100644
--- a/src/ipa/simple/algorithms/blc.cpp
+++ b/src/ipa/simple/algorithms/blc.cpp
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 /*
- * Copyright (C) 2024, Red Hat Inc.
+ * Copyright (C) 2024-2025, Red Hat Inc.
  *
  * Black level handling
  */
@@ -38,6 +38,9 @@ int BlackLevel::init([[maybe_unused]] IPAContext &context,
 int BlackLevel::configure(IPAContext &context,
 			  [[maybe_unused]] const IPAConfigInfo &configInfo)
 {
+	exposure_ = 0;
+	gain_ = 0;
+
 	if (definedLevel_.has_value())
 		context.configuration.black.level = definedLevel_;
 	context.activeState.blc.level =
-- 
2.48.1