I believe this should not be enabled, and that applications should be trained to write 32-bit linear samples instead.
The reason being that it's very confusing how exactly 24-bit samples should be encoded, and different applications and implementations have different ideas. In OSSv4, S24 means "24-bit samples packed into 32-bit words". It has a separate AFMT_S24_PACKED for 24-bit samples packed into 24-bit words. FreeBSD does not appear to support the PACKED format, only using 4 bytes per sample. Solaris does support the PACKED format when using OSSv4, and appears to use it internally. For the Sun API, the intention is to use 3 bytes per sample. For Sun .au files (which our audio interface is closely mapped to), in Solaris 24-bit explicitly means 3 bytes per sample. I think the confusing situation means that a lot of applications will be broken.
