From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH] x86/quirks: disable HPET on Intel Coffee Lake Refresh platforms
Date: Tue,  3 Dec 2019 21:57:16 +0100

This is a follow up of fc5db58539b4 ("x86/quirks: Disable HPET on Intel
Coffe Lake platforms"), which addressed the issue for 8th generation
Coffee Lake. Intel has released Coffee Lake again for 9th generation,
apparently still with the same bug:

clocksource: timekeeping watchdog on CPU3: Marking clocksource 'tsc' as unstable because the skew is too large:
clocksource:                       'hpet' wd_now: 24f422b8 wd_last: 247dea41 mask: ffffffff
clocksource:                       'tsc' cs_now: 144d927c4e cs_last: 140ba6e2a0 mask: ffffffffffffffff
tsc: Marking TSC unstable due to clocksource watchdog
TSC found unstable after boot, most likely due to broken BIOS. Use 'tsc=unstable'.
sched_clock: Marking unstable (26553416234, 4203921)<-(26567277071, -9656937)
clocksource: Switched to clocksource hpet

So, we add another quirk for the chipset

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
---
 arch/x86/kernel/early-quirks.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
index 4cba91ec8049..a73f88dd7f86 100644
--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c
@@ -716,6 +716,8 @@ static struct chipset early_qrk[] __init
 		PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet},
 	{ PCI_VENDOR_ID_INTEL, 0x8a12,
 		PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet},
+	{ PCI_VENDOR_ID_INTEL, 0x3e20,
+		PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet},
 	{ PCI_VENDOR_ID_BROADCOM, 0x4331,
 	  PCI_CLASS_NETWORK_OTHER, PCI_ANY_ID, 0, apple_airport_reset},
 	{}