On Wed, Apr 12, 2017 at 09:01:32PM +0100, Chris Wilson wrote: > On Thu, Apr 13, 2017 at 05:05:27AM +1000, Dave Airlie wrote: > > >> > > >> Not sure what the best semantics are there, any opinions on barring > > >> wakeups/polling on semaphore sync_files, and just punting this > > >> until we need it. > > > > > > I think getting it right now will make writing sw_sync-esque (i.e. cpu) > > > tests easier and more complete. > > > > I just don't have any use case for it, so we would be writing code to > > write tests for it. > > > > That doesn't seem smart. > > > > If there is a future non-testing use case, the API is expressive > > enough for someone > > to add a flag or new sync obj to allow polling and to add support in a > > nice easily > > digestible patch. > > My first thought was to check the signaled status would be to use > poll(0), but that can be retrieved from the sync_file_status ioctl. But > to get that still needs for us to acquire an fd from the syncobj. And if > we were to want check the flag on a driver syncobj, we would need to be > able to export one. That doesn't look very promising... Hmm, you do export fd to pass syncobj between processes. Let's not start with syncobj being a second class sync_file. -Chris -- Chris Wilson, Intel Open Source Technology Centre
