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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Peter Zijlstra <peterz@infradead.org>,
        Paul Menzel <pmenzel@molgen.mpg.de>
Cc:     x86@kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: TSC problems with Acer TravelMate 5735Z
In-Reply-To: <20200524185800.GV325280@hirez.programming.kicks-ass.net>
References: <a8c0c572-6dba-8d35-69bd-5e7b19bf6aba@molgen.mpg.de> <20200524185800.GV325280@hirez.programming.kicks-ass.net>
Date:   Thu, 28 May 2020 14:06:17 +0200
Message-ID: <874ks0p8li.fsf@nanos.tec.linutronix.de>
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Peter Zijlstra <peterz@infradead.org> writes:
> On Sun, May 24, 2020 at 07:09:18PM +0200, Paul Menzel wrote:
>> Dear Linux folks,
>> 
>> 
>> I got my hands on an old Acer TravelMate 5735Z (Intel GM45/Cantiga) and
>> installed Debian Sid/unstable with Linux 5.6.7 on it.
>> 
>> Booting the system it takes a long time, and the systemd units fail to
>> start. The logs contain that the TSC is unstable. Adding `tsc=unstable` to
>> the Linux kernel command line fixes this.
>
> It fixes nothing; it just doesn't get you the warning because you told
> it upfront.

Well, it prevents the kernel to use TSC upfront and not wait until it's
discovered to be crap. That might make a difference.

Thanks,

        tglx