Raspberry Pi Working On A "More Normal" Media Stack

Eric Anholt of Broadcom's latest open-source Linux driver work hasn't been on their BCMV Vulkan driver or their newer VC5 Gallium3D driver, but rather improving the multimedia stack for existing Raspberry Pi devices.

With their new code they are "building a more normal media stack for the platform, I want to get this upstreamed," explained Eric Anholt.

The current Raspberry Pi media stack is largely out of tree and a bit of a hodge-podge mess assembled over the years and not using all of the modern and mainline APIs. It's great to hear a new media stack will be on the way and one that is upstream.

Eric has spent time this past week working on VCHI probing for the upstream Raspberry Pi. VCHI is the kernel to VideoCore communication interface and central to its media support. There's been VCHI support in the Linux kernel's staging area for audio and camera components.

There's also been work recently on the new VCSM (VideoCore Shared Memory) service support that still needs to be upstreamed. The VCSM code also ties into the new V4L2 mem2mem driver being worked on by Broadcom developers.

But back on the VC4 side, with the performance counters support landing in DRM-Next for Linux 4.17, the latest VC4 Mesa code now has the "perfmon" performance monitoring support of OpenGL workloads on the hardware.

More details on this recent open-source Broadcom media/graphics work via Eric's blog.