Hi Liyang,
On 08/24/17 at 11:54am, Dou Liyang wrote:
> > > Test in my own PC(Lenovo M4340).
> > > Ask help for doing regression testing for the bug said in commit
> > > c4e1acbb35e4
> > > ("ACPI / init: Invoke early ACPI initialization later").
> > >
> >
> > Now, I can prove this patch doesn't result in the bug[1] which made the
> > fast TSC calibration using PIT failed in a Thinkpad x121e (AMD E-450
> > APU).
> >
> > The true reason of the bug is enabling ACPI subsystem earlier than
> > using PIT, not the SCI setup. invoking acpi_enable_subsystem() later
Seems redhat mail server was down earlier, I didn't receive new mail in
this thread. Just curious, do you know why the fast tsc calibration
using PIT will fail if enabling ACPI subsystem earlier than using PIT?
Thanks
Baoquan
> > could fix this bug as Julian tested and said[2].
> >
> > And, I found that Commit b064a8fa77df (" ACPI / init: Switch over
> > platform to the ACPI mode later") split the ACPI early initialization
> > code into acpi_early_init() and acpi_subsystem_init(). executing
> > acpi_enable_subsystem() at the original early ACPI initialization spot.
> >
> > The sequence of them shows below:
> >
> > start_kernel
> > +---------------+
> > |
> > +--> .......
> > |
> > | late_time_init()
> > +--> +-------+
> > |
> > +--> .......
> > |
> > | acpi_early_init()
> > +--> +-------+
> > |
> > +--> .......
> > |
> > | acpi_subsystem_init()
> > +-> +--------+
> >
> > We make sure the acpi_subsystem_init() is called later than
> > late_time_init(), the bug will be avoided.
> >
> > This patch changes the sequence of late_time_init() and
> > acpi_early_init(), doesn't effect acpi_subsystem_init().
> >
> > So, this patch is OK.
> >
> > Btw, Thanks very much for Borislav Petkov, he will have access to
> > Thinkpad x121e from Mid-August and will test this series.
> >
>
> Almost one month passed, Borislav have tested this series in Thinkpad
> x121e and I also have tested in my box and QEmu again. It is OK.
>
> BTW,
> 1) I found your commit b064a8fa77df (" ACPI / init: Switch over
> platform to the ACPI mode later") split the ACPI early initialization
> code into acpi_early_init() and acpi_subsystem_init(). Actually enabling
> the ACPI subsystem is in acpi_subsystem_init().
>
> 2) As we discussed earlier, invoking acpi_put_table() is not good for
> this situation.
>
> So I do this patch, Is that goot to you? Any comments will be welcome.
>
> If it is OK, As the patches need to be re-based, and I also found
> several spelling mistake, I will send a new version next week.
>
> Thanks,
> dou.
>
> > [1] https://lkml.org/lkml/2014/3/10/123
> > [2] https://lkml.org/lkml/2014/3/12/311
> >
> >
> > Thanks
> > dou.
> >
> > > init/main.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/init/main.c b/init/main.c
> > > index df58a41..7a09467 100644
> > > --- a/init/main.c
> > > +++ b/init/main.c
> > > @@ -654,12 +654,12 @@ asmlinkage __visible void __init start_kernel(void)
> > > kmemleak_init();
> > > setup_per_cpu_pageset();
> > > numa_policy_init();
> > > + acpi_early_init();
> > > if (late_time_init)
> > > late_time_init();
> > > calibrate_delay();
> > > pidmap_init();
> > > anon_vma_init();
> > > - acpi_early_init();
> > > #ifdef CONFIG_X86
> > > if (efi_enabled(EFI_RUNTIME_SERVICES))
> > > efi_enter_virtual_mode();
> > >
>
>
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