linux-kernel - Re: [PATCH] x86/tsc: Unset TSC_KNOWN_FREQ and TSC

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Date:   Wed, 18 Dec 2019 17:26:06 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Vipul Kumar <vipulk0511@...il.com>
Cc:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org, Stable <stable@...r.kernel.org>,
        Srikanth Krishnakar <Srikanth_Krishnakar@...tor.com>,
        Cedric Hombourger <Cedric_Hombourger@...tor.com>,
        Vipul Kumar <vipul_kumar@...tor.com>
Subject: Re: [PATCH] x86/tsc: Unset TSC_KNOWN_FREQ and TSC_RELIABLE flags on
 Intel Bay Trail SoC

On Wed, Dec 18, 2019 at 09:00:39PM +0530, Vipul Kumar wrote:
> From: Vipul Kumar <vipul_kumar@...tor.com>
> 
> 'commit f3a02ecebed7 ("x86/tsc: Set TSC_KNOWN_FREQ and TSC_RELIABLE
> flags on Intel Atom SoCs")', causing time drift for Bay trail SoC.
> These flags are set for SoCs having cpuid_level 0x15 or more.
> Bay trail is having cpuid_level 0xb.
> 
> So, unset both flags to make sure the clocksource calibration can
> be done.
> 
> Signed-off-by: Vipul Kumar <vipul_kumar@...tor.com>
> ---
>  arch/x86/kernel/tsc_msr.c | 3 +++
>  1 file changed, 3 insertions(+)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>