On Wednesday, March 12, 2014 12:00:07 PM joeyli wrote: > Hi Julian, > > 於 二，2014-03-11 於 18:15 +0100，Julian Wollrath 提到： > > Am Tue, 11 Mar 2014 14:56:41 +0100 (CET) > > schrieb Thomas Gleixner <t...@linutronix.de>: > > > > Ok, via bisecting I found commit > > > > 73f7d1ca32638028e3271f54616773727e2f9f26 (see below) to be the one > > > > that introduced this regression. > > > > > > Interesting. I have no idea what's going on. But maybe can the ACPI > > > folks shed some light on it. > > > > My patch moved acpi_early_init() to before timekeeping_init() is for > prepare the later using ACPI TAD to set system clock. I think that > because acpi_early_init() setup SCI interrupt and enable acpi subsystem, > it causes fast TSC calibration fail. > > > I have absolutely no idea, if it is the right thing to do and why it > > works, but the patch below fixes the problem. Thank you for your help. > > > > > > Cheers, > > Julian Wollrath > > > > From 7664f495039d93adfce073e58840a46549904f04 Mon Sep 17 00:00:00 2001 > > From: Julian Wollrath <jwollr...@web.de> > > Date: Tue, 11 Mar 2014 18:05:43 +0100 > > Subject: [PATCH] Fix fast TSC calibration > > > > Since commit 73f7d1ca32638028e3271f54616773727e2f9f26 the fast TSC > > calibration > > failed on a Thinkpad X121e with an AMD E450 APU. Moving acpi_early_init() > > after > > late_time_init() fixes this. > > > > Signed-off-by: Julian Wollrath <jwollr...@web.de> > > --- > > init/main.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/init/main.c b/init/main.c > > index eb03090cdced..bf9d99148bd6 100644 > > --- a/init/main.c > > +++ b/init/main.c > > @@ -561,7 +561,6 @@ asmlinkage void __init start_kernel(void) > > init_timers(); > > hrtimers_init(); > > softirq_init(); > > - acpi_early_init(); > > timekeeping_init(); > > time_init(); > > sched_clock_postinit(); > > @@ -609,6 +608,7 @@ asmlinkage void __init start_kernel(void) > > numa_policy_init(); > > if (late_time_init) > > late_time_init(); > > + acpi_early_init(); > > sched_clock_init(); > > calibrate_delay(); > > pidmap_init(); > > The late_time_init() dependent on timekeeping_init(), if we don't want > move acpi_early_init() before timekeeping_init() then just direct put it > before efi_enter_virtual_mode() because we tested this changed. > > This patch restricts the position to run acpi_early_init() before > timekeeping_init() when only "CMOS RTC Not Present" bit set in FADT. > > Could you please help to test it on your machine? > > > Thanks a lot! > Joey Lee > > > >From 8ef4fff76dd2f50bef1e8eb9c96f3b0228a38401 Mon Sep 17 00:00:00 2001 > From: Lee, Chun-Yi <j...@suse.com> > Date: Wed, 12 Mar 2014 11:36:32 +0800 > Subject: [PATCH] ACPI / init: Run acpi_early_init() before timekeeping_init() > when CMOS RTC Not Present bit set > > This is a variant patch from Rafael J. Wysocki's > ACPI / init: Run acpi_early_init() before efi_enter_virtual_mode() > > According to Matt Fleming, if acpi_early_init() was executed before > efi_enter_virtual_mode(), the EFI initialization could benefit from > it, so Rafael's patch makes that happen. > > And, later we want accessing ACPI TAD device to set system clock, so > move acpi_early_init() before timekeeping_init() when "CMOS RTC Not > Present" bit set. This position is also before efi_enter_virtual_mode(). > > Signed-off-by: Lee, Chun-Yi <j...@suse.com> > --- > init/main.c | 7 ++++++- > 1 files changed, 6 insertions(+), 1 deletions(-) > > diff --git a/init/main.c b/init/main.c > index eb03090..e1b69d2 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -561,7 +561,9 @@ asmlinkage void __init start_kernel(void) > init_timers(); > hrtimers_init(); > softirq_init(); > - acpi_early_init(); > + if (acpi_gbl_FADT.header.revision >= 5 && > + acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) > + acpi_early_init();
Sorry, this is not the right way to address that. First of all, checking fields in acpi_gbl_FADT from anything in init/main.c is wrong. If anything, please move that check to acpi_early_init(). And make it check it if it's been called already. > timekeeping_init(); > time_init(); > sched_clock_postinit(); > @@ -613,6 +615,9 @@ asmlinkage void __init start_kernel(void) > calibrate_delay(); > pidmap_init(); > anon_vma_init(); > + if (!(acpi_gbl_FADT.header.revision >= 5 && > + acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC)) > + acpi_early_init(); And then you can call it here again. > #ifdef CONFIG_X86 > if (efi_enabled(EFI_RUNTIME_SERVICES)) > efi_enter_virtual_mode(); > But I wonder: Can we simply enable SCI later? In other words, can we split acpi_early_init() so that the part before acpi_enable_subsystem() is done before timekeeping_init() and the part including and after is done right after anon_vma_init()? Would the TAD initialization work then? -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
