[libcamera-devel] [PATCH v3 4/5] libcamera: control_serializer: Serialize info::def()

[Jacopo Mondi]

The ControlInfo class was originally designed to only transport
the control's minimum and maximum values which represent the control's
valid limits.

Later the default value of the control has been added to the ControlInfo
class, but the control serializer implementation has not been updated
accordingly.

This causes issues in IPA modules making use of ControlInfo::def() as,
when running in isolation, they would receive 0.

Fix that by serializing and deserializing the additional ControlValue
and update the protocol description accordingly.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/libcamera/control_serializer.cpp |  6 ++++--
 src/libcamera/ipa_controls.cpp       | 14 ++++++++------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/libcamera/control_serializer.cpp b/src/libcamera/control_serializer.cpp
index d42840cddecb..f1245ea620ab 100644
--- a/src/libcamera/control_serializer.cpp
+++ b/src/libcamera/control_serializer.cpp
@@ -105,7 +105,7 @@ size_t ControlSerializer::binarySize(const ControlValue &value)
 
 size_t ControlSerializer::binarySize(const ControlInfo &info)
 {
-	return binarySize(info.min()) + binarySize(info.max());
+	return binarySize(info.min()) + binarySize(info.max()) + binarySize(info.def());
 }
 
 /**
@@ -158,6 +158,7 @@ void ControlSerializer::store(const ControlInfo &info, ByteStreamBuffer &buffer)
 {
 	store(info.min(), buffer);
 	store(info.max(), buffer);
+	store(info.def(), buffer);
 }
 
 /**
@@ -346,8 +347,9 @@ ControlInfo ControlSerializer::loadControlInfo(ControlType type,
 
 	ControlValue min = loadControlValue(type, b);
 	ControlValue max = loadControlValue(type, b);
+	ControlValue def = loadControlValue(type, b);
 
-	return ControlInfo(min, max);
+	return ControlInfo(min, max, def);
 }
 
 /**
diff --git a/src/libcamera/ipa_controls.cpp b/src/libcamera/ipa_controls.cpp
index fb98cda30ede..c3489bbff646 100644
--- a/src/libcamera/ipa_controls.cpp
+++ b/src/libcamera/ipa_controls.cpp
@@ -108,17 +108,19 @@
  *           +-------------------------+       .
  *         / | ...                     |       | entry[n].offset
  *         | +-------------------------+ <-----´
- *    Data | | minimum value (#n)      | \
- * section | +-------------------------+ | Entry #n
- *         | | maximum value (#n)      | /
+ *         | | minimum value (#n)      | \
+ *    Data | +-------------------------+ |
+ * section | | maximum value (#n)      | | Entry #n
+ *         | +-------------------------+ |
+ *         | | default value (#n)      | /
  *         | +-------------------------+
  *         \ | ...                     |
  *           +-------------------------+
  * ~~~~
  *
- * The minimum and maximum value are stored in the platform's native data
- * format. The ipa_control_info_entry::offset field stores the offset from the
- * beginning of the data section to the info data.
+ * The minimum, maximum and default values are stored in the platform's native
+ * data format. The ipa_control_info_entry::offset field stores the offset from
+ * the beginning of the data section to the info data.
  *
  * Info data in the data section shall be stored in the same order as the
  * entries array, shall be aligned to a multiple of 8 bytes, and shall be
-- 
2.32.0