On Mon, Jun 11, 2012 at 11:54:03AM -0400, Nicolas Pitre wrote:

Many CPUs are implementing power saving states via the WFI mode.
In some cases, WFI must be entered in order to suspend, or even reset,
a CPU.

Whether a CPU needs to be awaken, brought out of WFI during secondary
boot, or to cancel a reset state before it is effective, the CPU must
receive an interrupt to exit its WFI state.

Let's formalize an IPI number for this purpose, and move over existing
users over to a convenience function for it.

This also has the side effect of removing the spurious "Unknown IPI
message 1" each time a CPU is awaken.

I want people to move over to using IPI 0 for wakeup.

The problem is, as ever, no one bloody well listens and they all continue
on copying Realview.