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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>
This commit is contained in:
Len Brown 2011-04-01 15:19:23 -04:00
parent 3b70b2e5fc
commit 99c6322143
2 changed files with 12 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
Documentation/feature-removal-schedule.txt
View File

@ -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

2
arch/x86/kernel/apm_32.c
View File

@ -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;