[PATCH] Make cpufreq_transition_notifier a raw notifier

[Alan Stern]

On Thu, 25 May 2006, Johannes Berg wrote:

> On Thu, 2006-05-25 at 13:53 -0400, Alan Stern wrote:
> 
> > Here's the patch Andrew asked for.  I have no idea whether it will solve 
> > any of these problems, and I'm certain that in the long run we shouldn't 
> > keep it.  Perhaps it will at least help stabilize 2.6.17.
> > 
> > It's up to you guys to see if the patch helps at all and to decide whether 
> > or not it should be applied.
> 
> Maybe I should note that I don't actually have seen any problems because
> of this, the kernel just warns about it. I guess that's because the
> semaphore won't ever actually be contended at that point.

The problem isn't contention for the semaphore.  The problem is that 
down_read() will enable interrupts even when the semaphore is not in 
contention, but parts of the cpufreq notifier chain need to execute with 
interrupts disabled.

Alan Stern