The current kernel (3.8.13) does not include the rts_pstor module which is needed for RTS5209 card readers and similar (e.g. built in for some Fujitsu Lifebooks). This module has been removed in kernels 3.8 and later without replacement. Installation of the sys-block/rts_pstor package fails (see attached log). Masking of 3.8.13 kernel does not allow any other kernel to be installed as the amd64 keyword is missing (only ~amd64).
Created attachment 349464 [details] Build log for sys-block/rts_pstor
Fixed in cvs, thanks for reporting.