On Tue, Nov 12, 2024 at 6:37 AM Len Brown lenb@kernel.org wrote:

From: Len Brown len.brown@intel.com

Under some conditions, MONITOR wakeups on Lunar Lake processors can be lost, resulting in significant user-visible delays.

Add LunarLake to X86_BUG_MONITOR so that wake_up_idle_cpu() always sends an IPI, avoiding this potential delay.

Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219364

Cc: stable@vger.kernel.org # 6.11 Signed-off-by: Len Brown len.brown@intel.com

So again

Reviewed-by: Rafael J. Wysocki rafael.j.wysocki@intel.com

and see one super-minor nit below.

---

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 e7656cbef68d..284cd561499c 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -586,7 +586,9 @@ 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))
  

I would put the || at the end of the previous line, that is

•       (c->x86_vfm == INTEL_ATOM_GOLDMONT ||
  

•        c->x86_vfm == INTEL_LUNARLAKE_M))
  

            set_cpu_bug(c, X86_BUG_MONITOR);

#ifdef CONFIG_X86_64

2.43.0