tree c6bc6d198536772cd50d08c6772e291c5ba91f31
parent d79df630f622806c4d0e116fbaf6ebf6baf53461
author Tejun Heo <tj@kernel.org> 1215231050 +0900
committer Linus Torvalds <torvalds@linux-foundation.org> 1215288337 -0700

ahci: give another shot at clearing all bits in irq_stat

Commit ea0c62f7cf70f13a67830471b613337bd0c9a62e tried to clear all
bits in irq_stat but it didn't actually achieve that as irq_stat was
anded with port_map right after read.  This patch makes ahci driver
always use the unmasked value to clear irq_status.

While at it, add explanation on the peculiarities of ahci IRQ
clearing.

This was spotted by Linus Torvalds.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>