On Thu, Aug 20, 2020 at 12:05:29PM +0200, Tomasz Figa wrote:

The UAPI and V4L2/videobuf2 changes are in good shape and the only
wrong part is the use of DMA API, which was based on an earlier email
guidance anyway, and a change to the synchronization part . I find
conclusions like the above insulting for people who put many hours
into designing and implementing the related functionality, given the
complexity of the videobuf2 framework and how ill-defined the DMA API
was, and would feel better if such could be avoided in future
communication.

It wasn't meant to be too insulting, but I found this out when trying
to figure out how to just disable it.  But it also ends up using
the actual dma attr flags for it's own consistency checks, so just
not setting the flag did not turn out to work that easily.

But in general it helps to add a few more people to the Cc list for
such things that do stranger things.  Especially if you think you did
it based on the advice of those people.