iris: implement threaded context callbacks for resource busy checking
This allows u_threaded_context to reuse idle buffers, map them asynchronously, and avoid reallocating them unnecessarily.
See commit 2fad90dc in radeonsi.
This allows u_threaded_context to reuse idle buffers, map them asynchronously, and avoid reallocating them unnecessarily.
See commit 2fad90dc in radeonsi.