When Steam runs, it mutes all input from the Steam Controller and instead registers a virtual gamepad that obeys the Big Picture controller remapping. We want to make sure to pick that one, since the "real" Steam Controller doesn't report any events while the virtual device is active. So we carefully consider the "real" Steam Controller "inactive" if the presence of the virtual device is detected, until the virtual device is disconnected (ie. when Steam is closed) or if it turns out that it is generating events after all, in which case it gets automatically reactivated.
This is a bit of a hack, maybe there is a cleaner way of doing this.
rdb
Rishabh Tewari
Sam Edwards
Mitchell Stokes