6.6-stable review patch. If anyone has any objections, please let me know.
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From: Len Brown len.brown@intel.com
[ Upstream commit c9a4b55431e5220347881e148725bed69c84e037 ]
Under some conditions, MONITOR wakeups on Lunar Lake processors can be lost, resulting in significant user-visible delays.
Add Lunar Lake to X86_BUG_MONITOR so that wake_up_idle_cpu() always sends an IPI, avoiding this potential delay.
Reported originally here:
https://bugzilla.kernel.org/show_bug.cgi?id=219364
[ dhansen: tweak subject ]
Signed-off-by: Len Brown len.brown@intel.com Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Reviewed-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/a4aa8842a3c3bfdb7fe9807710eef159cbf0e705.1731463... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/cpu/intel.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 78f34ff32c9b..97259485c111 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -666,7 +666,9 @@ static void init_intel(struct cpuinfo_x86 *c) c->x86_vfm == INTEL_WESTMERE_EX)) set_cpu_bug(c, X86_BUG_CLFLUSH_MONITOR);
- if (boot_cpu_has(X86_FEATURE_MWAIT) && c->x86_vfm == INTEL_ATOM_GOLDMONT) + if (boot_cpu_has(X86_FEATURE_MWAIT) && + (c->x86_vfm == INTEL_ATOM_GOLDMONT || + c->x86_vfm == INTEL_LUNARLAKE_M)) set_cpu_bug(c, X86_BUG_MONITOR);
#ifdef CONFIG_X86_64