bcm2835-codec: Return empty buffers to the VPU instead of queueing to… #4961
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… vbuf2 The encoder can skip frames totally should rate control overshoot the target bitrate too far. In this situation it generates an output buffer of length 0. V4L2 treats a buffer of length 0 as an end of stream flag, which is not appropriate in this case, therefore we can not return that buffer to the client. The driver was returning the buffer to videobuf2 in the QUEUED state, however that buffer was then not dequeued again, so the number of buffers was reduced each time this happened. In the pathological case of using GStreamer's videotestsrc in mode 1 for noise, this happens sufficiently frequently to totally stall the pipeline. If the port is still enabled then return the buffer straight back to the VPU rather than to videobuf2. Signed-off-by: Dave Stevenson <[email protected]>
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…ueing to vbuf2 See: raspberrypi/linux#4961 kernel: overlays/rpi-display: Add support for DRM driver See: raspberrypi/linux#4959 kernel: backport: drm/tiny: Add MIPI DBI compatible SPI driver See: raspberrypi/linux#4954 kernel: drivers: staging: bcm2835-isp: Clear LS table handle in the firmware See: raspberrypi/linux#4952
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…ueing to vbuf2 See: raspberrypi/linux#4961 kernel: overlays/rpi-display: Add support for DRM driver See: raspberrypi/linux#4959 kernel: backport: drm/tiny: Add MIPI DBI compatible SPI driver See: raspberrypi/linux#4954 kernel: drivers: staging: bcm2835-isp: Clear LS table handle in the firmware See: raspberrypi/linux#4952
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… vbuf2
The encoder can skip frames totally should rate control overshoot
the target bitrate too far. In this situation it generates an
output buffer of length 0.
V4L2 treats a buffer of length 0 as an end of stream flag, which is
not appropriate in this case, therefore we can not return that buffer
to the client.
The driver was returning the buffer to videobuf2 in the QUEUED state,
however that buffer was then not dequeued again, so the number of
buffers was reduced each time this happened. In the pathological
case of using GStreamer's videotestsrc in mode 1 for noise, this happens
sufficiently frequently to totally stall the pipeline.
If the port is still enabled then return the buffer straight back to
the VPU rather than to videobuf2.
Signed-off-by: Dave Stevenson [email protected]