v3dv: implement events
This reverts a previous half-attempt at an implementation of events
using a BO to hold the event state, and provides a full
implementation. V3D doesn't have any built-in GPU functionality to
wait on any kind of events, so we need to implement this in the driver
an therefore we no longer need to use a BO for the event state.
Instead, we implement GPU waits by using a CPU job for the wait
operation that spawns a wait thread if the wait operation doesn't have
all its events signaled by the time it is processed. To implement the
semantics of the wait correctly, any jobs in the same command buffer
that come after the wait will not be emitted until the wait thread
completes.
If a submit spawns any wait threads for a command buffer we can't
signal any semaphores for it until all the wait threads complete and
we know that all the jobs for those command buffers have been
submitted. The same applies to the submit fence, if present.
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
4 files changed
