x86/quirks: Disable HPET on Intel Coffe Lake platforms
authorKai-Heng Feng <kai.heng.feng@canonical.com>
Wed, 16 Oct 2019 10:38:16 +0000 (18:38 +0800)
committerThomas Gleixner <tglx@linutronix.de>
Tue, 12 Nov 2019 14:55:20 +0000 (15:55 +0100)
commitfc5db58539b49351e76f19817ed1102bf7c712d0
tree07aeb9357412b8cc139f1aeba853e2482ac6fde9
parent31f4f5b495a62c9a8b15b1c3581acd5efeb9af8c
x86/quirks: Disable HPET on Intel Coffe Lake platforms

Some Coffee Lake platforms have a skewed HPET timer once the SoCs entered
PC10, which in consequence marks TSC as unstable because HPET is used as
watchdog clocksource for TSC.

Harry Pan tried to work around it in the clocksource watchdog code [1]
thereby creating a circular dependency between HPET and TSC. This also
ignores the fact, that HPET is not only unsuitable as watchdog clocksource
on these systems, it becomes unusable in general.

Disable HPET on affected platforms.

Suggested-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203183
Link: https://lore.kernel.org/lkml/20190516090651.1396-1-harry.pan@intel.com/
Link: https://lkml.kernel.org/r/20191016103816.30650-1-kai.heng.feng@canonical.com
arch/x86/kernel/early-quirks.c