[libcamera-devel] [PATCH v3 0/5] Raspberry Pi: Efficient start/stop/start sequences

[Naushir Patuck]

Hi Laurent,

On Mon, 21 Mar 2022 at 13:02, Laurent Pinchart <
laurent.pinchart at ideasonboard.com> wrote:

> On Mon, Mar 21, 2022 at 10:26:57AM +0000, Naushir Patuck via
> libcamera-devel wrote:
> > Hi,
> >
> > For version 3 of this series, I've removed the patch to add a timer that
> waits
> > for 5s after stop() to de-allocate buffers.  David and me have had a
> chat about
> > this and we think for now it is best that we have fully deterministic
> behavior for
> > buffer allocations, and avoid CMA fragmentation on the Raspberry Pi
> platforms.
>
> For what it's worth, I agree about the deterministic behaviour. We can
> work on top of this series to add a hint to the stop() function to tell
> the pipeline handler if streaming is expected to be restarted soon.
>

I had a think about this briefly over the weekend, and I wonder if it might
be better to
have a new API function freeResources() type call instead of a flag in
stop()? This would
allow the application to separate out the two actions if it so desires.

Naush


>
> > Apart from that, I have renamed the reallocate flag based on Kieran's
> suggestion.
> >
> > Regards,
> > Naush
> >
> > Naushir Patuck (5):
> >   pipeline: raspberrypi: Avoid over-allocation for ISP Output 1
> >   pipeline: raspberrypi: Move freeBuffers() to the RPiCameraData class
> >   pipeline: raspberrypi: Free buffers in the RPiCamera destructor and
> >     re-configure
> >   pipeline: raspberrypi: Repurpose RPi::Stream::reset()
> >   libcamera: v4l2_videodevice: Empty the V4L2 buffer cache on
> >     streamOff()
> >
> >  include/libcamera/internal/v4l2_videodevice.h |  1 +
> >  .../pipeline/raspberrypi/raspberrypi.cpp      | 58 ++++++++++++-------
> >  .../pipeline/raspberrypi/rpi_stream.cpp       | 13 ++---
> >  .../pipeline/raspberrypi/rpi_stream.h         |  2 +-
> >  src/libcamera/v4l2_videodevice.cpp            | 16 +++++
> >  5 files changed, 61 insertions(+), 29 deletions(-)
>
> --
> Regards,
>
> Laurent Pinchart
>
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