6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Len Brown <len.brown@xxxxxxxxx> commit c9a4b55431e5220347881e148725bed69c84e037 upstream. 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@xxxxxxxxx> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Cc:stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/all/a4aa8842a3c3bfdb7fe9807710eef159cbf0e705.1731463305.git.len.brown%40intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/cpu/intel.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -586,7 +586,9 @@ static void init_intel(struct cpuinfo_x8 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
