If a driver can definitely see available devices, it is chosen. Otherwise,
 we'll take the first driver that initializes but saw no devices...this might
 be because it can't enumerate them, or there really aren't any available.

This prevents the dsp driver from hogging control when there are no /dev/dsp*
 nodes (for example, on a Linux box with ALSA and no OSS emulation).

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%403400