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libcamera: v4l2_videodevice: Identify non-zero stream starts

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V4L2 Video devices should always start streaming from index zero.
Identify and report a warning if they don't, and correct for any offset.

Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
This commit is contained in:
Kieran Bingham 2022-05-02 16:42:49 +02:00
parent 27cc0a6b58
commit 1c9dc0fd89
2 changed files with 16 additions and 0 deletions
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1
include/libcamera/internal/v4l2_videodevice.h
View file

@ -276,6 +276,7 @@ private:
EventNotifier *fdBufferNotifier_;
State state_;
std::optional<unsigned int> firstFrame_;
Timer watchdog_;
utils::Duration watchdogDuration_;

15
src/libcamera/v4l2_videodevice.cpp
View file

@ -1771,6 +1771,19 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer()
if (V4L2_TYPE_IS_OUTPUT(buf.type))
return buffer;
/*
* Detect kernel drivers which do not reset the sequence number to zero
* on stream start.
*/
if (!firstFrame_) {
if (buf.sequence)
LOG(V4L2, Warning)
<< "Zero sequence expected for first frame (got "
<< buf.sequence << ")";
firstFrame_ = buf.sequence;
}
buffer->metadata_.sequence -= firstFrame_.value();
unsigned int numV4l2Planes = multiPlanar ? buf.length : 1;
FrameMetadata &metadata = buffer->metadata_;
@ -1847,6 +1860,8 @@ int V4L2VideoDevice::streamOn()
{
int ret;
firstFrame_.reset();
ret = ioctl(VIDIOC_STREAMON, &bufferType_);
if (ret < 0) {
LOG(V4L2, Error)