From: Thomas Gleixner <tglx@linutronix.de>
To: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
harry.pan@intel.com, x86@kernel.org,
LKML <linux-kernel@vger.kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH] x86/hpet: Disable HPET on Intel Coffe Lake
Date: Thu, 29 Aug 2019 21:45:00 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1908292143300.1938@nanos.tec.linutronix.de> (raw)
In-Reply-To: <793CCD4F-35E0-46B9-B5D4-3D3233BA5D35@canonical.com>
[-- Attachment #1: Type: text/plain, Size: 1592 bytes --]
On Thu, 29 Aug 2019, Kai-Heng Feng wrote:
> at 20:13, Thomas Gleixner <tglx@linutronix.de> wrote:
> > On Thu, 29 Aug 2019, Kai-Heng Feng wrote:
> >
> > > Some Coffee Lake platforms have skewed HPET timer once the SoCs entered
> > > PC10, and marked TSC as unstable clocksource as result.
> >
> > So here you talk about Coffee Lake and in the patch you use KABYLAKE.
>
> Coffeelake has the same model number as Kabylake.
Yeah, just a bit more text explaining that would be helpful.
> > > +static const struct x86_cpu_id hpet_blacklist[] __initconst = {
> > > + { X86_VENDOR_INTEL, 6, INTEL_FAM6_KABYLAKE_MOBILE },
> > > + { X86_VENDOR_INTEL, 6, INTEL_FAM6_KABYLAKE_DESKTOP },
> >
> > So this disables HPET on all Kaby Lake variants not just on the affected
> > Coffee Lakes. I know that I rejected the initial patch with the random
> > stepping cutoff...
> >
> > https://lore.kernel.org/lkml/alpine.DEB.2.21.1904081403220.1748@nanos.tec.linutronix.de
> >
> > In the other attempt to 'fix' this I asked for clarification, but silence
> > from Intel after this:
> >
> > https://lore.kernel.org/lkml/alpine.DEB.2.21.1905182015320.3019@nanos.tec.linutronix.de
> >
> > Can Intel please provide some useful information about this finally?
>
> Hopefully Intel can provide more info.
>
> I know we should find the root cause rather than stopping at "it’s a firmware
> bug”, but users are already affected by this issue [1].
> Is there any better short-term workaround?
Not really. And if Intel stays silent, I'm just going to apply it as is
along with a stable tag.
Thanks,
tglx
next prev parent reply other threads:[~2019-08-29 19:45 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-29 9:12 [PATCH] x86/hpet: Disable HPET on Intel Coffe Lake Kai-Heng Feng
2019-08-29 12:13 ` Thomas Gleixner
2019-08-29 14:13 ` Kai-Heng Feng
2019-08-29 19:45 ` Thomas Gleixner [this message]
2019-08-29 21:38 ` [RFD] x86/tsc: Loosen the requirements for watchdog - (was x86/hpet: Disable HPET on Intel Coffe Lake) Thomas Gleixner
2019-08-30 3:47 ` Daniel Drake
2019-10-01 15:47 ` [PATCH] x86/hpet: Disable HPET on Intel Coffe Lake Kai-Heng Feng
2019-10-09 5:58 ` Feng Tang
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