aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorLen Brown2011-04-01 15:41:17 -0400
committerLen Brown2011-05-29 03:39:16 -0400
commitcdaab4a0d330f70c0e5ad8c3f7c65c2e375ea180 (patch)
treec0737c6c9106f858df5e223b168d548de1c1990e
parent99c63221435963e0cee2402686ba99293c2ffa9e (diff)
x86 idle: deprecate "no-hlt" cmdline param
We'd rather that modern machines not check if HLT works on every entry into idle, for the benefit of machines that had marginal electricals 15-years ago. If those machines are still running the upstream kernel, they can use "idle=poll". The only difference will be that they'll now invoke HLT in machine_hlt(). cc: x86@kernel.org # .39.x Signed-off-by: Len Brown <len.brown@intel.com>
-rw-r--r--Documentation/feature-removal-schedule.txt11
-rw-r--r--arch/x86/kernel/cpu/bugs.c1
2 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index fc505c1b4762..f1b0eb02aa1d 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -24,6 +24,17 @@ Who: Len Brown <len.brown@intel.com>
----------------------------
+What: x86_32 "no-hlt" cmdline param
+When: 2012
+Why: remove a branch from idle path, simplify code used by everybody.
+ This option disabled the use of HLT in idle and machine_halt()
+ for hardware that was flakey 15-years ago. Today we have
+ "idle=poll" that removed HLT from idle, and so if such a machine
+ is still running the upstream kernel, "idle=poll" is likely sufficient.
+Who: Len Brown <len.brown@intel.com>
+
+----------------------------
+
What: PRISM54
When: 2.6.34
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index c39576cb3018..525514cf33c3 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -19,6 +19,7 @@
static int __init no_halt(char *s)
{
+ WARN_ONCE(1, "\"no-hlt\" is deprecated, please use \"idle=poll\"\n");
boot_cpu_data.hlt_works_ok = 0;
return 1;
}