lkml.org 
[lkml]   [2009]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: System clock runs too fast after 2.6.27 -> 2.6.28.1 upgrade

    * john stultz <johnstul@us.ibm.com> wrote:

    > On Fri, 2009-01-23 at 00:57 +0100, Miklos Vajna wrote:
    > > On Thu, Jan 22, 2009 at 12:03:14PM -0800, john stultz
    > > > CONFIG_X86_VISWS: If I recall, this is support for SGI workstations that
    > > > had different apics then most systems, and might be related.
    > > >
    > > I just did a new build with CONFIG_X86_VISWS and CONFIG_X86_RDC321X
    > > disabled, but I kept CONFIG_PARAVIRT_GUEST enabled and that works fine
    > > as well. So CONFIG_PARAVIRT_GUEST seems to be unrelated.
    >
    > Ah. CONFIG_X86_RDC321X is indeed the issue.
    >
    > >From arch/x86/include/asm/timex.h:
    >
    > #ifdef CONFIG_X86_ELAN
    > # define PIT_TICK_RATE 1189200 /* AMD Elan has different frequency! */
    > #elif defined(CONFIG_X86_RDC321X)
    > # define PIT_TICK_RATE 1041667 /* Underlying HZ for R8610 */
    > #else
    > # define PIT_TICK_RATE 1193182 /* Underlying HZ */
    > #endif
    >
    > This gives the kernel an incorrect slower frequency for the PIT hardware
    > on your system and is why the TSC calibration is off and why the ACPI PM
    > gets thrown out.
    >
    > I'd think this would ideally be more of a subarch in the config
    > selection like the AMD Elan is, so folks know it really is not just a
    > extra-support feature and in fact limits what hardware you can use the
    > resulting kernel on.

    a better solution is that if RDC is set [it is unset by default] we should
    turn PIT_TICK_RATE into a variable, defaulting it to 1193182. If a real
    RDC or ELAN system is running, that variable is changed during early
    bootup, in the init functions for those platforms.

    Ingo


    \
     
     \ /
      Last update: 2009-01-23 12:07    [W:0.027 / U:30.000 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site