[PATCH] ARM:CPUIDLE: Fix wrongly used idle control counter

On Thu, Sep 27, 2012 at 02:36:01PM +0800, Fan Wu wrote:

From: fwu <redacted>

1. On ARM platform, "nohlt" can be used to prevent core from idle
   process, returning immediately.
2. There are two interface, exported for other modules, named
   disable_hlt and enable_hlt and used to enable/disable the
   cpuidle mechanism by increasing/decreasing "hlt_counter".
   So, the more "hlt_counter" is, the more user want to disable
   cpuidle. Disable_hlt and enable_hlt are paired operation,
   when you first call disable_hlt and then enable_hlt, the
   semantics are right, but if you call enable_hlt and
   then disable_hlt, it is wrong.
3. Change "hlt_counter > 0" can fix the problem.
   The judgement whethere the cpuidle is disabled need to check
   whether the "hlt_counter > 0" rather than "hlt_counter != 0".

NAK.  The bug is that you're calling enable_hlt() without first calling
disable_hlt().  That is something you _must_ _not_ do.

If the count starts off zero, and a driver calls disable_hlt(), another
driver _must_ _not_ override that by then calling enable_hlt().