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Commit cdaab4a0 authored Apr 01, 2011 by Len Brown

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>

parent 99c63221

Documentation/feature-removal-schedule.txt

+11 −0

Original line number	Diff line number	Diff line
		@@ -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

arch/x86/kernel/cpu/bugs.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}