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Commit 99c63221 authored Apr 01, 2011 by Len Brown

x86 idle APM: deprecate CONFIG_APM_CPU_IDLE



We don't want to export the pm_idle function pointer to modules.
Currently CONFIG_APM_CPU_IDLE w/ CONFIG_APM_MODULE forces us to.

CONFIG_APM_CPU_IDLE is of dubious value, it runs only on 32-bit
uniprocessor laptops that are over 10 years old.  It calls into
the BIOS during idle, and is known to cause a number of machines
to fail.

Removing CONFIG_APM_CPU_IDLE and will allow us to stop exporting
pm_idle.  Any systems that were calling into the APM BIOS
at run-time will simply use HLT instead.

cc: x86@kernel.org
cc: Jiri Kosina <jkosina@suse.cz>
cc: stable@kernel.org # .39.x
Signed-off-by: Len Brown <len.brown@intel.com>

parent 3b70b2e5

Documentation/feature-removal-schedule.txt

+10 −0

Original line number	Diff line number	Diff line
		@@ -14,6 +14,16 @@ Who: Len Brown <len.brown@intel.com>

		---------------------------

		What: CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle
		When: 2012
		Why: This optional sub-feature of APM is of dubious reliability,
		and ancient APM laptops are likely better served by calling HLT.
		Deleting CONFIG_APM_CPU_IDLE allows x86 to stop exporting
		the pm_idle function pointer to modules.
		Who: Len Brown <len.brown@intel.com>

		----------------------------

		What: PRISM54
		When: 2.6.34

arch/x86/kernel/apm_32.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -359,6 +359,7 @@ struct apm_user {
		* idle percentage above which bios idle calls are done
		*/
		#ifdef CONFIG_APM_CPU_IDLE
		#warning deprecated CONFIG_APM_CPU_IDLE will be deleted in 2012
		#define DEFAULT_IDLE_THRESHOLD 95
		#else
		#define DEFAULT_IDLE_THRESHOLD 100
		@@ -902,6 +903,7 @@ static void apm_cpu_idle(void)
		unsigned int jiffies_since_last_check = jiffies - last_jiffies;
		unsigned int bucket;

		WARN_ONCE(1, "deprecated apm_cpu_idle will be deleted in 2012");
		recalc:
		if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
		use_apm_idle = 0;