[XeTeX] no small caps in GNU FreeSerif font?

[Andy Lin]

The small caps glyphs are definitely there, but they might only be
considered part of the IPA extension range, i.e. they are not intended
as small caps for general use. Which seems weird to me. But anyhow,
this is a case where a teckit mapping could solve your problem. Or you
could file a ticket with the developers.

I can't check the OT features on the font right now on this machine,
but if you run otfinfo, it should tell you if the smcp feature is
present in the font (although it's not a sure test, considering Charis
SIL had, for older versions, the smcp flag, but no actual
implementation).

-Andy