Commit c9a4b554 authored by Len Brown's avatar Len Brown Committed by Dave Hansen
Browse files

x86/cpu: Add Lunar Lake to list of CPUs with a broken MONITOR implementation 

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: default avatarLen Brown <len.brown@intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/a4aa8842a3c3bfdb7fe9807710eef159cbf0e705.1731463305.git.len.brown%40intel.com
parent ae6012d7

arch/x86/kernel/cpu/intel.c

+3 −1
Original line number Diff line number Diff line
@@ -555,7 +555,9 @@ 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