Thread (22 messages) 22 messages, 6 authors, 2025-01-08

Re: [PATCH 0/7] Raspberry Pi HEVC decoder driver

From: Nicolas Dufresne <hidden>
Date: 2025-01-06 20:46:56
Also in: linux-arm-kernel, linux-media, lkml

Hi Dave,

Le vendredi 20 décembre 2024 à 16:21 +0000, Dave Stevenson a écrit :
Hi All

This has been in the pipeline for a while, but I've finally cleaned
up our HEVC decoder driver to be in a shape to at least get a first
review.
John Cox has done almost all of the work under contract to Raspberry
Pi, and I'm largely just doing the process of patch curation and
sending.

There are a couple of questions raised in frameworks.
The main one is that the codec has 2 independent phases to the decode,
CABAC and reconstruction. To keep the decoder operating optimally
means that two requests need to be in process at once, whilst the
current frameworks don't want to allow as there is an implicit
assumption of only a single job being active at once, and
completition returns both buffers and releases the media request.

The OUTPUT queue buffer is finished with and can be returned at the
end of phase 1, but the media request is still required for phase 2.
The frameworks currently force the driver to be returning both
together via v4l2_m2m_buf_done_and_job_finish. v4l2_m2m_job_finish
would complete the job without returning the buffer as we need,
however if the driver has set VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF
then we have a WARN in v4l2_m2m_job_finish.
Dropping the WARN as this series is currently doing isn't going to be
the right answer, but it isn't obvious what the right answer is.
Discussion required.
I think part of the manual request completion RFC will be to evaluate the impact
on VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF feature. MTK does not support
interleaved interlaced decoding (only alternate), so they didn't have to
implement that feature.

Overall, It would be nice to get your feedback on the new manual request
proposal, which is I believe better then the pin/unpin API you have in this
serie.
We also have a need to hold on to the media request for phase 2. John
had discussed this with Ezequiel (and others) a couple of years back,
and hence suggested a patch that adds media_request_{pin,unpin} to
grab references on the media request. Discussion required on that
or a better way of handling it.

I will apologise in advance for sending this V1 just before I head off
on the Christmas break, but will respond to things as soon as possible.
One thing missing in this summary is how this driver is being validated
(specially that for this one requires a downstream fork of FFMPEG). To this
report we ask for:

- v4l2-compliance results
- Fluster conformance tests results [1] and I believe you need [2]

[1] https://github.com/fluendo/fluster
[2] https://github.com/fluendo/fluster/pull/179

GStreamer support is there in main now, but without the needed software video
converter for you column tiling, we can't use it for that (i.e. only works
through GL or Wayland).

regards,
Nicolas
Thanks
  Dave

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
Dave Stevenson (4):
      docs: uapi: media: Document Raspberry Pi NV12 column format
      media: ioctl: Add pixel formats NV12MT_COL128 and NV12MT_10_COL128
      media: dt-bindings: media: Add binding for the Raspberry Pi HEVC decoder
      arm: dts: bcm2711-rpi: Add HEVC decoder node

Ezequiel Garcia (1):
      RFC: media: Add media_request_{pin,unpin} API

John Cox (2):
      media: platform: Add Raspberry Pi HEVC decoder driver
      RFC: v4l2-mem2mem: Remove warning from v4l2_m2m_job_finish

 .../bindings/media/raspberrypi,hevc-dec.yaml       |   72 +
 .../userspace-api/media/v4l/pixfmt-yuv-planar.rst  |   42 +
 MAINTAINERS                                        |   10 +
 arch/arm/boot/dts/broadcom/bcm2711-rpi.dtsi        |    5 +
 arch/arm/boot/dts/broadcom/bcm2711.dtsi            |    9 +
 drivers/media/mc/mc-request.c                      |   35 +
 drivers/media/platform/raspberrypi/Kconfig         |    1 +
 drivers/media/platform/raspberrypi/Makefile        |    1 +
 .../media/platform/raspberrypi/hevc_dec/Kconfig    |   17 +
 .../media/platform/raspberrypi/hevc_dec/Makefile   |    5 +
 .../media/platform/raspberrypi/hevc_dec/hevc_d.c   |  443 ++++
 .../media/platform/raspberrypi/hevc_dec/hevc_d.h   |  190 ++
 .../platform/raspberrypi/hevc_dec/hevc_d_h265.c    | 2629 ++++++++++++++++++++
 .../platform/raspberrypi/hevc_dec/hevc_d_hw.c      |  376 +++
 .../platform/raspberrypi/hevc_dec/hevc_d_hw.h      |  303 +++
 .../platform/raspberrypi/hevc_dec/hevc_d_video.c   |  685 +++++
 .../platform/raspberrypi/hevc_dec/hevc_d_video.h   |   38 +
 drivers/media/v4l2-core/v4l2-ioctl.c               |    2 +
 drivers/media/v4l2-core/v4l2-mem2mem.c             |    7 -
 include/media/media-request.h                      |   12 +
 include/uapi/linux/videodev2.h                     |    5 +
 21 files changed, 4880 insertions(+), 7 deletions(-)
---
base-commit: e90c9612ac3969cb8206029a26bcd2b6f5d4a942
change-id: 20241212-media-rpi-hevc-dec-3b5be739f3bd

Best regards,
  
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