Giving Rust a chance for in-kernel codecs

Posted Apr 29, 2024 16:42 UTC (Mon) by farnz (subscriber, #17727)
In reply to: Giving Rust a chance for in-kernel codecs by flussence
Parent article: Giving Rust a chance for in-kernel codecs

I think it's also worth calling out the DMA-BUF UAPI as a prerequisite for change. Without DMA-BUF, the only ways to move data between hardware blocks involve either copies into userspace memory, or having a subsystem-specific mechanism like the V4L2 media controller API to move data around in kernelspace within a single subsystem.

DMA-BUF enables you to export a handle to data to userspace, which can then pass it to a different kernel subsystem. This allows you to elide the copies, and export data from V4L2 to DRM, or from DRM to V4L2.