According to otfinfo, greek small capitals are supported in Minion Pro.
otfinfo --script=grek -f MinionPro-Regular.otf
...
smcp Small Capitals
...
yet the following MWE
\documentclass{article}
\usepackage{fontspec}
\setmainfont{Minion Pro}
\begin{document}
\textsc{Small Capitals}
\textsc{Πεζοκεφαλαία}
\end{document}
results in:
What option should I pass to fontspec in order to have small capitals with Minion Pro for greek Glyphs?
Best Answer
I think that the appropriate glyphs are not available. Using the MyFonts site for Minion Pro it is possible to do a 'live test' with text of your choice and picking small caps: .
As you can see, the result is identical to the TeX result - no small caps.