glk_schannel_set_volume(sc, 0x00000);
glk_schannel_set_volume(sc, 0xA0000); /* max supported volume */
glk_schannel_set_volume(sc, 0xB0000); /* should be coerced */
glk_schannel_set_volume(sc, 0x10000);
glk_schannel_set_volume(sc, 0x00000);
glk_schannel_set_volume(sc, 0xA0000); /* max supported volume */
glk_schannel_set_volume(sc, 0xB0000); /* should be coerced */
glk_schannel_set_volume(sc, 0x10000);