> I wonder what advantages the udmabuf driver has?
Hi there - author of the request (to add the kernel build option) here. The main motivation / the big advantage in my view is the fact udmabuf is available by default on most systems and distros, unlike dma_heaps (see https://github.com/systemd/systemd/issues/32662). That makes upstreaming of related code in software that doesn't target the PI specifically much easier. In fact we just landed an implementation for in Gstreamer (see https://gitlab.freedesktop.org/gstreame ... uests/8540), meaning that some video players will get better performance when using software video decoding in the upcoming 1.28 release on the PI 4 and 5.
So for the PI-centric software there shouldn't be much a difference if they already support dma heaps, however the PI ecosystem as a whole should benefit from more software using efficient upload paths - especially given that the PIs are particular sensitive to memory bandwidth usage and have limited hardware video decoder capabilities.
Hi there - author of the request (to add the kernel build option) here. The main motivation / the big advantage in my view is the fact udmabuf is available by default on most systems and distros, unlike dma_heaps (see https://github.com/systemd/systemd/issues/32662). That makes upstreaming of related code in software that doesn't target the PI specifically much easier. In fact we just landed an implementation for in Gstreamer (see https://gitlab.freedesktop.org/gstreame ... uests/8540), meaning that some video players will get better performance when using software video decoding in the upcoming 1.28 release on the PI 4 and 5.
So for the PI-centric software there shouldn't be much a difference if they already support dma heaps, however the PI ecosystem as a whole should benefit from more software using efficient upload paths - especially given that the PIs are particular sensitive to memory bandwidth usage and have limited hardware video decoder capabilities.
Statistics: Posted by rmader — Sun Dec 07, 2025 4:10 pm