Re: [PATCH v3 00/11] Add DELETE_BUF ioctl

[Hsia-Jun Li]

On 6/22/23 21:13, Benjamin Gaignard wrote:
> CAUTION: Email originated externally, do not click links or open attachments unless you recognize the sender and know the content is safe.
>
>
> Unlike when resolution change on keyframes, dynamic resolution change
> on inter frames doesn't allow to do a stream off/on sequence because
> it is need to keep all previous references alive to decode inter frames.
> This constraint have two main problems:
> - more memory consumption.
> - more buffers in use.
> To solve these issue this series introduce DELETE_BUF ioctl and remove
> the 32 buffers limit per queue.

I know the VIDIOC_CREATE_BUFS allows creating a buffer with a different 
size than the driver suggests in G_FMT.

But the vb2_ops->queue_setup() could check whether the sizeimages meet 
its minimal requirement with the current format.

This enables a problem that the driver need to check the buffer size 
before they make a hardware use a buffer from the rdy_queue.


Thinking of such case, we know a AV1 sequence(VP9 or VP8 didn't have a 
sequence header) would need a much large buffer for the alternative 
reference frame.

Then create one special buffer for the altref, the driver need a 
hardware to pick it from the rdy_queue first or it would be a waste to 
use it as a regular frame buffer.

Also missing such step would not solve the memory allocation problem.

> VP9 conformance tests using fluster give a score of 210/305.
> The 25 resize inter tests (vp90-2-21-resize_inter_* files) are ok
> but require to use postprocessor.
>
> Kernel branch is available here:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__gitlab.collabora.com_benjamin.gaignard_for-2Dupstream_-2D_commits_remove-5Fvb2-5Fqueue-5Flimit-5Fv3&d=DwIDAg&c=7dfBJ8cXbWjhc0BhImu8wVIoUFmBzj1s88r8EGyM0UY&r=P4xb2_7biqBxD4LGGPrSV6j-jf3C3xlR7PXU-mLTeZE&m=DCpeuc2fAyJ_XUCYsydYOB5ynn0uW4JsFKVbEiXj-6AhZ5d2vm3GkOClPl8cfN9U&s=8whob9PKPu98WlyK6J9DcmFFiDPbwI3ws-nLfWR0oTE&e=
>
> GStreamer branch to use DELETE_BUF ioctl and testing dynamic resolution
> change is here:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__gitlab.freedesktop.org_benjamin.gaignard1_gstreamer_-2D_commits_VP9-5Fdrc&d=DwIDAg&c=7dfBJ8cXbWjhc0BhImu8wVIoUFmBzj1s88r8EGyM0UY&r=P4xb2_7biqBxD4LGGPrSV6j-jf3C3xlR7PXU-mLTeZE&m=DCpeuc2fAyJ_XUCYsydYOB5ynn0uW4JsFKVbEiXj-6AhZ5d2vm3GkOClPl8cfN9U&s=SEexoIeuXbraR1zvtSkz0MQFGyZSeKQ7Pt6mJoNrS0A&e=
>
> changes in version 3:
> - Use Xarray API to store allocated video buffers.
> - No module parameter to limit the number of buffer per queue.
> - Use Xarray inside Verisilicon driver to store postprocessor buffers
>    and remove VB2_MAX_FRAME limit.
> - Allow Versilicon driver to change of resolution while streaming
> - Various fixes the Verisilicon VP9 code to improve fluster score.
>
> changes in version 2:
> - Use a dynamic array and not a list to keep trace of allocated buffers.
>    Not use IDR interface because it is marked as deprecated in kernel
>    documentation.
> - Add a module parameter to limit the number of buffer per queue.
> - Add DELETE_BUF ioctl and m2m helpers.
>
> Benjamin Gaignard (11):
>    media: videobuf2: Access vb2_queue bufs array through helper functions
>    media: videobuf2: Use Xarray instead of static buffers array
>    media: videobuf2: Remove VB2_MAX_FRAME limit on buffer storage
>    media: videobuf2: Stop define VB2_MAX_FRAME as global
>    media: verisilicon: Refactor postprocessor to store more buffers
>    media: verisilicon: Store chroma and motion vectors offset
>    media: verisilicon: vp9: Use destination buffer height to compute
>      chroma offset
>    media: verisilicon: postproc: Fix down scale test
>    media: verisilicon: vp9: Allow to change resolution while streaming
>    media: v4l2: Add DELETE_BUF ioctl
>    media: v4l2: Add mem2mem helpers for DELETE_BUF ioctl
>
>   .../userspace-api/media/v4l/user-func.rst     |   1 +
>   .../media/v4l/vidioc-delete-buf.rst           |  51 ++++
>   .../media/common/videobuf2/videobuf2-core.c   | 275 ++++++++++++++----
>   .../media/common/videobuf2/videobuf2-v4l2.c   |  34 ++-
>   drivers/media/platform/amphion/vdec.c         |   1 +
>   drivers/media/platform/amphion/vpu_dbg.c      |  22 +-
>   .../platform/mediatek/jpeg/mtk_jpeg_core.c    |   6 +-
>   .../vcodec/vdec/vdec_vp9_req_lat_if.c         |   4 +-
>   drivers/media/platform/qcom/venus/hfi.h       |   2 +
>   drivers/media/platform/st/sti/hva/hva-v4l2.c  |   4 +
>   drivers/media/platform/verisilicon/hantro.h   |   8 +-
>   .../platform/verisilicon/hantro_g2_vp9_dec.c  |  10 +-
>   .../media/platform/verisilicon/hantro_hw.h    |   4 +-
>   .../platform/verisilicon/hantro_postproc.c    | 114 +++++---
>   .../media/platform/verisilicon/hantro_v4l2.c  |  37 +--
>   drivers/media/test-drivers/vim2m.c            |   1 +
>   drivers/media/test-drivers/visl/visl-dec.c    |  28 +-
>   drivers/media/v4l2-core/v4l2-dev.c            |   1 +
>   drivers/media/v4l2-core/v4l2-ioctl.c          |  10 +
>   drivers/media/v4l2-core/v4l2-mem2mem.c        |  20 ++
>   .../staging/media/atomisp/pci/atomisp_ioctl.c |   2 +-
>   drivers/staging/media/ipu3/ipu3-v4l2.c        |   2 +
>   include/media/v4l2-ioctl.h                    |   4 +
>   include/media/v4l2-mem2mem.h                  |  12 +
>   include/media/videobuf2-core.h                |  16 +-
>   include/media/videobuf2-v4l2.h                |  15 +-
>   include/uapi/linux/videodev2.h                |   2 +
>   27 files changed, 523 insertions(+), 163 deletions(-)
>   create mode 100644 Documentation/userspace-api/media/v4l/vidioc-delete-buf.rst
>
> --
> 2.39.2
--
Hsia-Jun(Randy) Li