diff options
| -rw-r--r-- | include/libcamera/internal/v4l2_device.h | 1 | ||||
| -rw-r--r-- | src/libcamera/v4l2_device.cpp | 22 |
2 files changed, 23 insertions, 0 deletions
diff --git a/include/libcamera/internal/v4l2_device.h b/include/libcamera/internal/v4l2_device.h index affe52c2..a647c96a 100644 --- a/include/libcamera/internal/v4l2_device.h +++ b/include/libcamera/internal/v4l2_device.h @@ -45,6 +45,7 @@ public: const std::string &deviceNode() const { return deviceNode_; } std::string devicePath() const; + bool supportsFrameStartEvent(); int setFrameStartEnabled(bool enable); Signal<uint32_t> frameStart; diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp index 2f65a43a..0db92c19 100644 --- a/src/libcamera/v4l2_device.cpp +++ b/src/libcamera/v4l2_device.cpp @@ -450,6 +450,28 @@ std::string V4L2Device::devicePath() const } /** + * \brief Check if frame start event is supported + * + * Due to limitations in the kernel API, this function may disable the frame + * start event as a side effect. It should only be called during initialization, + * before enabling the frame start event with setFrameStartEnabled(). + * + * \return True if frame start event is supported, false otherwise + */ +bool V4L2Device::supportsFrameStartEvent() +{ + struct v4l2_event_subscription event{}; + event.type = V4L2_EVENT_FRAME_SYNC; + + int ret = ioctl(VIDIOC_SUBSCRIBE_EVENT, &event); + if (ret) + return false; + + ioctl(VIDIOC_UNSUBSCRIBE_EVENT, &event); + return true; +} + +/** * \brief Enable or disable frame start event notification * \param[in] enable True to enable frame start events, false to disable them * |