2.4.26 doesn't boot on a 386 without "Unsynced TSC support"

From: Erik Mouw (erik_at_harddisk-recovery.com)
Date: 07/28/04

  • Next message: Karim Yaghmour: "Re: [patch] IRQ threads" 
    Date:	Wed, 28 Jul 2004 17:47:49 +0200
To: linux-kernel@vger.kernel.org

    Hi,

    I tried to boot 2.4.26 on my good old 386 board, but got a kernel
    panic:

      CPU: 386
      Kernel panic: Kernel compiled for Pentium+, requires TSC feature!

    The error message comes from the function check_config() in
    include/asm-i386/bugs.h (thanks to wli for figuring out faster than I
    did).

    I am sure I selected support for a 80386 CPU, so the error message
    looks wrong to me. CONFIG_M586TSC is not set, but CONFIG_X86_TSC is
    enabled by default. The only way to disable it, is to enable "Unsynced
    TSC support", (CONFIG_X86_TSC_DISABLE).

    The help for CONFIG_X86_TSC_DISABLE mentions to use it for "NUMA
    mult-mode boxes, laptops and other systems suffering from unsynced TSCs
    or TSC drift, which can cause gettimeofday to return non-monotonic
    values." A simple 80386 board doesn't belong to these, and I can't
    remember having problmes with gettimeofday() in the past (IIRC the
    board last ran linux-1.2 or 2.0).

    My question is: is this a code bug, or a documentation bug? Right now,
    I guess 2.4.26 will not run on anything < Pentium without
    CONFIG_X86_TSC_DISABLE enabled.

    Erik 

    -- 
+-- Erik Mouw -- www.harddisk-recovery.com -- +31 70 370 12 90 --
| Lab address: Delftechpark 26, 2628 XH, Delft, The Netherlands
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  • Next message: Karim Yaghmour: "Re: [patch] IRQ threads"

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