From 16f3d2de50ffa35295240e247d8cc4cffabf1a53 Mon Sep 17 00:00:00 2001 From: Naushir Patuck Date: Wed, 6 Apr 2022 13:35:52 +0100 Subject: libcamera: v4l2_videodevice: Add a dequeue timer Add a timer that gets reset on every buffer dequeue event. If the timeout expires, optionally call a slot in the pipeline handler to handle this condition. This may be useful in detecting and handling stalls in either the hardware or device driver. Signed-off-by: Naushir Patuck Reviewed-by: Kieran Bingham Reviewed-by: Laurent Pinchart Signed-off-by: Laurent Pinchart --- src/libcamera/v4l2_videodevice.cpp | 53 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) (limited to 'src/libcamera') diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp index 0830be80..c3a1b6c4 100644 --- a/src/libcamera/v4l2_videodevice.cpp +++ b/src/libcamera/v4l2_videodevice.cpp @@ -539,6 +539,7 @@ V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode) V4L2VideoDevice::V4L2VideoDevice(const MediaEntity *entity) : V4L2VideoDevice(entity->deviceNode()) { + watchdog_.timeout.connect(this, &V4L2VideoDevice::watchdogExpired); } V4L2VideoDevice::~V4L2VideoDevice() @@ -1726,6 +1727,9 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer() return nullptr; } + if (watchdogDuration_.count()) + watchdog_.start(std::chrono::duration_cast(watchdogDuration_)); + cache_->put(buf.index); FrameBuffer *buffer = it->second; @@ -1828,6 +1832,8 @@ int V4L2VideoDevice::streamOn() } state_ = State::Streaming; + if (watchdogDuration_.count()) + watchdog_.start(std::chrono::duration_cast(watchdogDuration_)); return 0; } @@ -1852,6 +1858,9 @@ int V4L2VideoDevice::streamOff() if (state_ != State::Streaming && queuedBuffers_.empty()) return 0; + if (watchdogDuration_.count()) + watchdog_.stop(); + ret = ioctl(VIDIOC_STREAMOFF, &bufferType_); if (ret < 0) { LOG(V4L2, Error) @@ -1879,6 +1888,50 @@ int V4L2VideoDevice::streamOff() return 0; } +/** + * \brief Set the dequeue timeout value + * \param[in] timeout The timeout value to be used + * + * Sets a timeout value, given by \a timeout, that will be used by a watchdog + * timer to ensure buffer dequeue events are periodically occurring when the + * device is streaming. The watchdog timer is only active when the device is + * streaming, so it is not necessary to disable it when the device stops + * streaming. The timeout value can be safely updated at any time. + * + * If the timer expires, the \ref V4L2VideoDevice::dequeueTimeout signal is + * emitted. This can typically be used by pipeline handlers to be notified of + * stalled devices. + * + * Set \a timeout to 0 to disable the watchdog timer. + */ +void V4L2VideoDevice::setDequeueTimeout(utils::Duration timeout) +{ + watchdogDuration_ = timeout; + + watchdog_.stop(); + if (watchdogDuration_.count() && state_ == State::Streaming) + watchdog_.start(std::chrono::duration_cast(timeout)); +} + +/** + * \var V4L2VideoDevice::dequeueTimeout + * \brief A Signal emitted when the dequeue watchdog timer expires + */ + +/** + * \brief Slot to handle an expired dequeue timer + * + * When this slot is called, the time between successive dequeue events is over + * the required timeout. Emit the \ref V4L2VideoDevice::dequeueTimeout signal. + */ +void V4L2VideoDevice::watchdogExpired() +{ + LOG(V4L2, Warning) + << "Dequeue timer of " << watchdogDuration_ << " has expired!"; + + dequeueTimeout.emit(); +} + /** * \brief Create a new video device instance from \a entity in media device * \a media -- cgit v1.2.1