• Kevin Hilman's avatar
    cpuidle: always return with interrupts enabled · 246eb7f0
    Kevin Hilman authored
    In the case where cpuidle_idle_call() returns before changing state due to
    a need_resched(), it was returning with IRQs disabled.
    
    The idle path assumes that the platform specific idle code returns with
    interrupts enabled (although this too is undocumented AFAICT) and on ARM
    we have a WARN_ON(!(irqs_disabled()) when returning from the idle loop, so
    the user-visible effects were only a warning since interrupts were
    eventually re-enabled later.
    
    On x86, this same problem exists, but there is no WARN_ON() to detect it.
    As on ARM, the interrupts are eventually re-enabled, so I'm not sure of
    any actual bugs triggered by this.  It's primarily a
    correctness/consistency fix.
    
    This patch ensures IRQs are (re)enabled before returning.
    Reported-by: default avatarHemanth V <hemanthv@ti.com>
    Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
    Cc: Arjan van de Ven <arjan@linux.intel.com>
    Cc: Len Brown <len.brown@intel.com>
    Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
    Tested-by: default avatarMartin Michlmayr <tbm@cyrius.com>
    Cc: <stable@kernel.org>		[2.6.31.x]
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    246eb7f0
cpuidle.c 8.54 KB