tree ba6bfdc216de500f3b3c7c1613c50efb7d550dba
parent bb1657468152c5e5232c7bf35cf0e9c41b5d9910
author Benjamin Herrenschmidt <benh@kernel.crashing.org> 1119908192 -0700
committer Linus Torvalds <torvalds@ppc970.osdl.org> 1119910302 -0700

[PATCH] ppc32: Bump PMU interrupt priority

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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>