The Montreux Jazz Festival has been the stage for Carlos Santana and John McLaughlin several times, but the sometimes partners played together at the annual event for the first time in 2011. The guitarists chose to perform most of the music from their esteemed 1973 album, Love Devotion Surrender. Some of the cover choices are odd—“Stairway to Heaven” works but “A Hard Rain’s A-Gonna Fall,” shorn of its poetry, has little to give musically. However, their original songs burn with controlled intensity, a mounting flame of emotional power and commitment.