Re: [PATCH v6 0/6] Raspberry Pi HEVC decoder driver

From: Jonas Karlman

Date: Thu Mar 05 2026 - 11:20:33 EST

Hi Dave,

On 3/4/2026 3:05 PM, Dave Stevenson wrote:
> 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 upstream.
> 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.
>
> Thanks
> Dave
>
> v4l2-compliance 1.33.0-5448, 64 bits, 64-bit time_t
> v4l2-compliance SHA: bd0aabb96710 2026-02-09 17:38:28
>
> Compliance test for rpi-hevc-dec device /dev/video0:
>
> Driver Info:
> Driver name : rpi-hevc-dec
> Card type : rpi-hevc-dec
> Bus info : platform:rpi-hevc-dec
> Driver version : 6.19.0
> Capabilities : 0x84204000
> Video Memory-to-Memory Multiplanar
> Streaming
> Extended Pix Format
> Device Capabilities
> Device Caps : 0x04204000
> Video Memory-to-Memory Multiplanar
> Streaming
> Extended Pix Format
> Detected Stateless Decoder
> Media Driver Info:
> Driver name : rpi-hevc-dec
> Model : rpi-hevc-dec
> Serial :
> Bus info : platform:rpi-hevc-dec
> Media version : 6.19.0
> Hardware revision: 0x00000000 (0)
> Driver version : 6.19.0
> Interface Info:
> ID : 0x0300000c
> Type : V4L Video
> Entity Info:
> ID : 0x00000001 (1)
> Name : rpi-hevc-dec-source
> Function : V4L2 I/O
> Pad 0x01000002 : 0: Source
> Link 0x02000008: to remote pad 0x1000004 of entity 'rpi-hevc-dec-proc' (Video Decoder): Data, Enabled, Immutable
>
> Required ioctls:
> test MC information (see 'Media Driver Info' above): OK
> test VIDIOC_QUERYCAP: OK
> test invalid ioctls: OK
>
> Allow for multiple opens:
> test second /dev/video0 open: OK
> test VIDIOC_QUERYCAP: OK
> test VIDIOC_G/S_PRIORITY: OK
> test for unlimited opens: OK
>
> Debug ioctls:
> test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
> test VIDIOC_LOG_STATUS: OK (Not Supported)
>
> Input ioctls:
> test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
> test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
> test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)
> test VIDIOC_ENUMAUDIO: OK (Not Supported)
> test VIDIOC_G/S/ENUMINPUT: OK (Not Supported)
> test VIDIOC_G/S_AUDIO: OK (Not Supported)
> Inputs: 0 Audio Inputs: 0 Tuners: 0
>
> Output ioctls:
> test VIDIOC_G/S_MODULATOR: OK (Not Supported)
> test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
> test VIDIOC_ENUMAUDOUT: OK (Not Supported)
> test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)
> test VIDIOC_G/S_AUDOUT: OK (Not Supported)
> Outputs: 0 Audio Outputs: 0 Modulators: 0
>
> Input/Output configuration ioctls:
> test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
> test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
> test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
> test VIDIOC_G/S_EDID: OK (Not Supported)
>
> Control ioctls:
> test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK
> test VIDIOC_QUERYCTRL: OK
> test VIDIOC_G/S_CTRL: OK
> fail: v4l2-test-controls.cpp(942): try_ext_ctrls returned an error (22)
> test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL
> test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK
> test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
> Standard Controls: 3 Private Controls: 0
> Standard Compound Controls: 5 Private Compound Controls: 0
>
> Format ioctls:
> test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK
> test VIDIOC_G/S_PARM: OK (Not Supported)
> test VIDIOC_G_FBUF: OK (Not Supported)
> test VIDIOC_G_FMT: OK
> test VIDIOC_TRY_FMT: OK
> test VIDIOC_S_FMT: OK
> test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)
> test Cropping: OK (Not Supported)
> test Composing: OK (Not Supported)
> test Scaling: OK (Not Supported)
>
> Codec ioctls:
> test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)
> test VIDIOC_G_ENC_INDEX: OK (Not Supported)
> test VIDIOC_(TRY_)DECODER_CMD: OK
>
> Buffer ioctls:
> test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: OK
> test CREATE_BUFS maximum buffers: OK
> test VIDIOC_REMOVE_BUFS: OK
> test VIDIOC_EXPBUF: OK
> test Requests: OK
> test blocking wait: OK
>
> Total for rpi-hevc-dec device /dev/video0: 49, Succeeded: 48, Failed: 1, Warnings: 0
>
> Testing is with a downstream patchset to FFmpeg. I'm told FFmpeg
> currently has no stateless decode support, but we will be reviewing
> works that have been in progress and our downstream patches to see
> whether that can be pushed onwards.

Please see FFmpeg PR20847 "Add V4L2 Request API hwaccels for MPEG2,
H.264, HEVC, VP8, VP9 and AV1" [1] for pending upstream FFmpeg work.

My 4l2request-v3-pixfmts branch [2] also contains extra commit to make
it work with downstream rpi kernel version, using non-MT pixfmts.

I will give this a spin together with the FFmpeg PR, adding support for
the MT based pixfmts should hopefully be easy.

[1] https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20847
[2] https://code.ffmpeg.org/Kwiboo/FFmpeg/commits/branch/v4l2request-v3-pixfmts

Regards,
Jonas

> Downstream tree is at
> https://github.com/jc-kynesim/rpi-ffmpeg/tree/test/7.1.2/main
>
> https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/9247
> adds support for the new formats to GStreamer, and runs Fluster.
> Using the JCT-VC-HEVC_V1 test suite we get 142 passes out of 147 tests.
> PICSIZE_[ABCD]_Bossen_1 all fail due to the image sizes being greater than
> the 4096x4096 limit of this driver.
> TSUNEQBD_A_MAIN10_Technicolor_2 fails as the hardware doesn't support
> having a different bit depth for luma and chroma.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> ---
> Changes in v6:
> - Fixed up assigned by unused variable (ctrl) in hevc_d_init_ctrls
> (reported by CI).
> - Fixed up documentation links (reported by CI)
> - Link to v5: https://lore.kernel.org/r/20260227-media-rpi-hevc-dec-v5-0-9bb3fc1816de@xxxxxxxxxxxxxxx
>
> Changes in v5:
> - Updated driver based on Nicolas' review comments of V4.
> - Added NV12MT_COL128 to ./drivers/media/v4l2-core/v4l2-common.c. The
> 10 bit format can't be represented with v4l2_format_info at present
> as it assumes a power of 2 block size.
> - Switched to kzalloc_obj/kzalloc_objs as checkpatch now checks that.
> - Link to v4: https://lore.kernel.org/r/20250701-media-rpi-hevc-dec-v4-0-057cfa541177@xxxxxxxxxxxxxxx
>
> Changes in v4:
> - dt-bindings: Drop to just SoC compatibles and updated description (Krzysztof).
> - dts: Corrected address in node name.
> - NV12MT_COL128 format description added vertical alignment to a
> multiple of 8 (Nicolas)
> - driver: Merged in driver updates based on Nicolas' review.
> - driver: Added debug module parameter to avoid log spam due to some bitstreams.
> - cover-letter: Added Fluster results.
> - rebased and based on the updated version of
> https://lore.kernel.org/linux-media/20250604-sebastianfricke-vcodec_manual_request_completion_with_state_machine-v3-0-603db4749d90@xxxxxxxxxxxxx/
> - update v4l2-compliance output
> - Link to v3: https://lore.kernel.org/r/20250423-media-rpi-hevc-dec-v3-0-8fd3fad1d6fb@xxxxxxxxxxxxxxx
>
> Changes in v3:
> - Updated the dtbinding with SoC specific compatible strings (Rob).
> - Reordered hevc_dec and v3d in bcm2711.dtsi to keep them in ascending
> register order (Stefan).
> - Reordered hevc_dec in bcm2711-rpi.dtsi to keep them in alphabetical
> order (Stefan).
> - Tested on top of Nicolas' revised version of Hans' patch set for
> manual request completion.
> https://lore.kernel.org/all/20250410-sebastianfricke-vcodec_manual_request_completion_with_state_machine-v2-0-5b99ec0450e6@xxxxxxxxxxxxx/
> - Link to v2: https://lore.kernel.org/r/20250206-media-rpi-hevc-dec-v2-0-69353c8805b2@xxxxxxxxxxxxxxx
>
> Changes in v2:
> - Rebased to use Hans' manual request completion scheme.
> https://lore.kernel.org/linux-media/cover.1724928939.git.hverkuil-cisco@xxxxxxxxx/
> - Require all slices for a frame to be submitted in one request.
> - Added the missing header file.
> - Used the full macro name for pix format docs (Sakari)
> - Dropped unneeded |- from dtbinding (Rob)
> - Made reg and reg-names match in order (Rob)
> - Removed clock-names from dtbinding (Rob)
> - Driver changed to not request the clock by name
> - Dropped clock-names from DTS file
> - Minor fixes for compliance failures
> fail: v4l2-test-formats.cpp(958): fmt_cap.g_colorspace() != col
> fail: v4l2-test-buffers.cpp(901): q.create_bufs(node, 1, &fmt) != EINVAL
> - v4l2-compliance output added to cover letter (Nicholas)
> I believe the "fail: v4l2-test-controls.cpp(939): try_ext_ctrls
> returned an error (22)" is expected as it is validating the SPS.
> Hantro and Cedrus certainly both appear to return errors in the same place
> - Link to v1: https://lore.kernel.org/r/20241220-media-rpi-hevc-dec-v1-0-0ebcc04ed42e@xxxxxxxxxxxxxxx
>
> ---
> Dave Stevenson (4):
> docs: uapi: media: Document Raspberry Pi NV12 column format
> media: ioctl: Add pixel formats NV12MT_COL128 and NV12MT_10_COL128
> dt-bindings: media: Add the Raspberry Pi HEVC decoder
> arm: dts: bcm2711-rpi: Add HEVC decoder node
>
> John Cox (2):
> docs: uapi: media: Clarify HEVC slice_param bit_size, data_byte_offset
> media: platform: Add Raspberry Pi HEVC decoder driver
>
> .../bindings/media/raspberrypi,hevc-dec.yaml | 72 +
> .../media/v4l/ext-ctrls-codec-stateless.rst | 6 +-
> .../userspace-api/media/v4l/pixfmt-yuv-planar.rst | 46 +
> MAINTAINERS | 10 +
> arch/arm/boot/dts/broadcom/bcm2711-rpi.dtsi | 4 +
> arch/arm/boot/dts/broadcom/bcm2711.dtsi | 9 +
> 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 | 325 +++
> .../media/platform/raspberrypi/hevc_dec/hevc_d.h | 195 ++
> .../platform/raspberrypi/hevc_dec/hevc_d_h265.c | 2436 ++++++++++++++++++++
> .../platform/raspberrypi/hevc_dec/hevc_d_h265.h | 22 +
> .../platform/raspberrypi/hevc_dec/hevc_d_hw.c | 429 ++++
> .../platform/raspberrypi/hevc_dec/hevc_d_hw.h | 317 +++
> .../platform/raspberrypi/hevc_dec/hevc_d_video.c | 634 +++++
> .../platform/raspberrypi/hevc_dec/hevc_d_video.h | 38 +
> drivers/media/v4l2-core/v4l2-common.c | 2 +
> drivers/media/v4l2-core/v4l2-ioctl.c | 2 +
> include/uapi/linux/videodev2.h | 4 +
> 21 files changed, 4573 insertions(+), 2 deletions(-)
> ---
> base-commit: 1512bd6430c7be7723724f31a74c3b8aaacf8a20
> change-id: 20241212-media-rpi-hevc-dec-3b5be739f3bd
>
> Best regards,