I saw this warning again this morning in one of the machines: GNOME Shell is unstable under classic-mode r300/r600 mesa drivers. Make sure that gallium architecture for r300 and r600 drivers is selected using 'eselect mesa'. But, for a long time, mesa is not even installing classic drivers for r300 and r600, then, the message is useless now
+ 30 Jun 2015; Pacho Ramos <pacho@gentoo.org> gnome-shell-3.16.2.ebuild: + Drop no longer needed warnings about r300/r600 (#553548) + + 30 Jun 2015; Pacho Ramos <pacho@gentoo.org> cinnamon-2.6.8.ebuild: + Drop no longer needed warnings about r300/r600 (#553548) +