[libcamera-devel] [PATCH v2 1/2] libcamera: camera_sensor: Fix frame lengths calculated by sensorInfo()

[David Plowman]

The minimum and maximum vblanking can change when a new format is
applied to the sensor subdevice, so be sure to retrieve up-to-date
values.

The V4L2Device acquires the new updateControlInfos() method to perform
this function, and which the CameraSensor calls automatically if its
setFormat method is used to update the sensor.

However, not all pipeline handlers invoke the setFormat method
directly, so the new method must be made publicly available for
pipeline handlers to call if they need to.

Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
---
 include/libcamera/internal/camera_sensor.h |  2 ++
 include/libcamera/internal/v4l2_device.h   |  2 ++
 src/libcamera/camera_sensor.cpp            | 31 +++++++++++++++++++++-
 src/libcamera/v4l2_device.cpp              | 26 ++++++++++++++++++
 4 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h
index 3e98f71b..c94744f0 100644
--- a/include/libcamera/internal/camera_sensor.h
+++ b/include/libcamera/internal/camera_sensor.h
@@ -68,6 +68,8 @@ public:
 	const ControlList &properties() const { return properties_; }
 	int sensorInfo(CameraSensorInfo *info) const;
 
+	void updateControlInfos();
+
 protected:
 	std::string logPrefix() const override;
 
diff --git a/include/libcamera/internal/v4l2_device.h b/include/libcamera/internal/v4l2_device.h
index d006bf68..274cbe65 100644
--- a/include/libcamera/internal/v4l2_device.h
+++ b/include/libcamera/internal/v4l2_device.h
@@ -41,6 +41,8 @@ public:
 	int setFrameStartEnabled(bool enable);
 	Signal<uint32_t> frameStart;
 
+	void updateControlInfos();
+
 protected:
 	V4L2Device(const std::string &deviceNode);
 	~V4L2Device();
diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index f7ed91d9..5dbe47a7 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -656,15 +656,30 @@ V4L2SubdeviceFormat CameraSensor::getFormat(const std::vector<unsigned int> &mbu
 /**
  * \brief Set the sensor output format
  * \param[in] format The desired sensor output format
+ *
+ * The sensor output format is set. The ranges of any controls associated
+ * with the sensor are also updated.
+ *
  * \return 0 on success or a negative error code otherwise
  */
 int CameraSensor::setFormat(V4L2SubdeviceFormat *format)
 {
-	return subdev_->setFormat(pad_, format);
+	int ret = subdev_->setFormat(pad_, format);
+
+	if (ret == 0)
+		updateControlInfos();
+
+	return ret;
 }
 
 /**
  * \brief Retrieve the supported V4L2 controls and their information
+ *
+ * Pipeline handlers that do not change the sensor format using the
+ * CameraSensor::setFormat method may need to call
+ * CameraSensor::updateControlInfos beforehand, to ensure all the control
+ * ranges are up to date.
+ *
  * \return A map of the V4L2 controls supported by the sensor
  */
 const ControlInfoMap &CameraSensor::controls() const
@@ -750,6 +765,11 @@ int CameraSensor::setControls(ControlList *ctrls)
  * Sensor information is only available for raw sensors. When called for a YUV
  * sensor, this function returns -EINVAL.
  *
+ * Pipeline handlers that do not change the sensor format using the
+ * CameraSensor::setFormat method may need to call
+ * CameraSensor::updateControlInfos beforehand, to ensure all the control
+ * ranges are up to date.
+ *
  * \return 0 on success, a negative error code otherwise
  */
 int CameraSensor::sensorInfo(CameraSensorInfo *info) const
@@ -821,6 +841,15 @@ int CameraSensor::sensorInfo(CameraSensorInfo *info) const
 	return 0;
 }
 
+/**
+ * \fn void CameraSensor::updateControlInfos()
+ * \brief Update the sensor's ControlInfos in case they have changed
+ */
+void CameraSensor::updateControlInfos()
+{
+	subdev_->updateControlInfos();
+}
+
 std::string CameraSensor::logPrefix() const
 {
 	return "'" + entity_->name() + "'";
diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index decd19ef..9678962c 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -514,6 +514,32 @@ void V4L2Device::listControls()
 	controls_ = std::move(ctrls);
 }
 
+/*
+ * \brief Update the control information that was previously stored by
+ * listControls(). Some parts of this information, such as min and max
+ * values of some controls, are liable to change when a new format is set.
+ */
+void V4L2Device::updateControlInfos()
+{
+	for (auto &controlId : controlIds_) {
+		unsigned int id = controlId->id();
+
+		struct v4l2_query_ext_ctrl ctrl = {};
+		ctrl.id = id;
+
+		if (ioctl(VIDIOC_QUERY_EXT_CTRL, &ctrl)) {
+			LOG(V4L2, Debug)
+				<< "Could not refresh control "
+				<< utils::hex(ctrl.id);
+			continue;
+		}
+
+		/* Assume these are present - listControls() made them. */
+		controlInfo_[id] = ctrl;
+		controls_.at(controlId.get()) = V4L2ControlInfo(ctrl);
+	}
+}
+
 /*
  * \brief Update the value of the first \a count V4L2 controls in \a ctrls using
  * values in \a v4l2Ctrls
-- 
2.20.1