• Benjamin Herrenschmidt's avatar
    [PATCH] ppc32: Bump PMU interrupt priority · e4ee69c8
    Benjamin Herrenschmidt authored
    The Power Management Unit on PowerMacs is very sensitive to timeouts during
    async message exchanges.  It uses rather crude protocol based on a shift
    register with an interrupt and is almost continuously exchanging messages with
    the host CPU on laptops.
    
    This patch adds a routine to the open_pic driver to be able to select a PMU
    driver so that it bumps it's interrupt priority to above the normal level.
    
    This will allow PMU interrupts to occur while another interrupt is pending,
    and thus reduce the risk of machine beeing abruptly shutdown by the PMU due to
    a timeout in PMU communication caused by excessive interrupt latency.  The
    problem is very rare, and usually just doesn't happen, but it is still useful
    to make things even more robust.
    Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    e4ee69c8
open_pic.c 28.1 KB