Allwinner VPU support in mainline Linux status update (week 26)

This week on the video player integration side, we focused on the last remaining bits for Kodi integration with our pipeline, with support for the H3 SoC. Unlike its predecessors, the untiling is done directly by the VPU itself and not by the display engine, which makes the overall integration easier. Allwinner platforms that come with version 2 of the display engine only support linear YUV formats, that is piped directly from the VPU. This makes our pipeline for these platforms slightly different from previous generations, since the VPU needs to be configured properly and no DRM format modifier needs to be carried around on the software side.

Thankfully, the code for enabling this output was already implemented by the linux-sunxi community in libvdpau-sunxi and only minor changes had to be added, in order to use the NV12 YUV format for the luma and chroma planes. Thanks to the help of the LibreELEC community members interested in Allwinner devices, who are as always very helpful when it comes to working with Kodi on Allwinner platforms, it was possible to pipe everything together on the H3 (and the DE2 DRM driver even received an initial patch for z-pos support, that allows re-ordering layers for alpha blending).

The result is visible in the following video, that shows Elephants Dream, an animation movie made with free software by the Blender Foundation and released under the Creative Commons Attribution 2.5 Generic license:

On the V4L2 kernel driver side, a rebase of the Sunxi-Cedrus driver on top of the latest kernel release candidate, 4.18-rc2 was completed and a number of features are being included in the series, including H3 support and support for the untiled NV12 video output. We expect to send a new iteration of the kernel driver patches next week.

We also discovered that the VPU untiling block is available on the A33 too, which will make supporting the A33 easier as well.

Finally, there was no progress on the H264 front this week, as Maxime was away on a business trip teaching a training. The progress on H264 will resume next week.

Author: Paul Kocialkowski

Paul is a kernel and embedded Linux intern at Bootlin. You can find more details about Paul on his personal website: http://www.paulk.fr/

5 thoughts on “Allwinner VPU support in mainline Linux status update (week 26)”

  1. Hi Paul, thank you very much for your blog. It is interesting to read, even though I do not understand every bit. I was also looking at https://linux-sunxi.org/Sunxi-cedrus but it hasn’t changed for a while, especially the ‘status’ tables. Enjoy and keep up the good work. Cheers Tido

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