On Sat, Mar 3, 2012 at 01:23, Sakari Ailus <sakari.ailus at iki.fi> wrote: > Where it should be decided which operations are being done to the buffer > when it is passed to user space and back to kernel space? > > How about spliting these operations to those done on the first time the > buffer is passed to the user space (mapping to kernel address space, for > example) and those required every time buffer is passed from kernel to user > and back (cache flusing)? > > I'm asking since any unnecessary time-consuming operations, especially as > heavy as mapping the buffer, should be avoidable in subsystems dealing > with streaming video, cameras etc., i.e. non-GPU users.
I'm a bit confused about your comments because this interface extension doesn't support userspace mmap. So userspace isn't even part of the picture. Adding mmap support is something entirely different imo, and I have no idea yet how we should handle cache coherency for that. Yours, Daniel -- Daniel Vetter daniel.vetter at ffwll.ch - +41 (0) 79 365 57 48 - http://blog.ffwll.ch
