Hi Greg, > On Nov 18, 2019, at 23:55, <gregkh@xxxxxxxxxxxxxxxxxxx> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > This is a note to let you know that I've just added the patch titled > > x86/quirks: Disable HPET on Intel Coffe Lake platforms > > to the 4.4-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > x86-quirks-disable-hpet-on-intel-coffe-lake-platforms.patch > and it can be found in the queue-4.4 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. This patch depends on commit c8c4076723da ("x86/timer: Skip PIT initialization on modern chipsets"). Otherwise the system may freeze at boot. So please also include that commit. Kai-Heng > > > From fc5db58539b49351e76f19817ed1102bf7c712d0 Mon Sep 17 00:00:00 2001 > From: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > Date: Wed, 16 Oct 2019 18:38:16 +0800 > Subject: x86/quirks: Disable HPET on Intel Coffe Lake platforms > > From: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > > commit fc5db58539b49351e76f19817ed1102bf7c712d0 upstream. > > 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@xxxxxxxxx> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203183 > Link: https://lore.kernel.org/lkml/20190516090651.1396-1-harry.pan@xxxxxxxxx/ [1] > Link: https://lkml.kernel.org/r/20191016103816.30650-1-kai.heng.feng@xxxxxxxxxxxxx > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > --- > arch/x86/kernel/early-quirks.c | 2 ++ > 1 file changed, 2 insertions(+) > > --- a/arch/x86/kernel/early-quirks.c > +++ b/arch/x86/kernel/early-quirks.c > @@ -699,6 +699,8 @@ static struct chipset early_qrk[] __init > */ > { PCI_VENDOR_ID_INTEL, 0x0f00, > PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet}, > + { PCI_VENDOR_ID_INTEL, 0x3ec4, > + 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}, > {} > > > Patches currently in stable-queue which might be from kai.heng.feng@xxxxxxxxxxxxx are > > queue-4.4/x86-quirks-disable-hpet-on-intel-coffe-lake-platforms.patch
