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Date: Wed, 12 Mar 2014 14:30:31 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: joeyli <jlee@...e.com>, Julian Wollrath <jwollrath@....de>
Cc: Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
LKML <linux-kernel@...r.kernel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [RESEND] Fast TSC calibration fails with v3.14-rc1 and later
On Wednesday, March 12, 2014 12:20:02 PM Rafael J. Wysocki wrote:
> 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 <tglx@...utronix.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 <jwollrath@....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 <jwollrath@....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 <jlee@...e.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 <jlee@...e.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?
Below is a patch implementing that idea. Julian, can you please test this one too?
Rafael
---
drivers/acpi/bus.c | 20 +++++++++++++++-----
include/linux/acpi.h | 1 +
init/main.c | 1 +
3 files changed, 17 insertions(+), 5 deletions(-)
Index: linux-pm/drivers/acpi/bus.c
===================================================================
--- linux-pm.orig/drivers/acpi/bus.c
+++ linux-pm/drivers/acpi/bus.c
@@ -494,11 +494,21 @@ void __init acpi_early_init(void)
}
status = acpi_load_tables();
- if (ACPI_FAILURE(status)) {
- printk(KERN_ERR PREFIX
- "Unable to load the System Description Tables\n");
- goto error0;
- }
+ if (ACPI_SUCCESS(status))
+ return;
+
+ printk(KERN_ERR PREFIX "Unable to load the System Description Tables\n");
+
+ error0:
+ disable_acpi();
+}
+
+void __init acpi_subsystem_init(void)
+{
+ acpi_status status;
+
+ if (acpi_disabled)
+ return;
#ifdef CONFIG_X86
if (!acpi_ioapic) {
Index: linux-pm/include/linux/acpi.h
===================================================================
--- linux-pm.orig/include/linux/acpi.h
+++ linux-pm/include/linux/acpi.h
@@ -401,6 +401,7 @@ extern acpi_status acpi_pci_osc_control_
#define ACPI_OST_SC_INSERT_NOT_SUPPORTED 0x82
extern void acpi_early_init(void);
+extern void acpi_subsystem_init(void);
extern int acpi_nvs_register(__u64 start, __u64 size);
Index: linux-pm/init/main.c
===================================================================
--- linux-pm.orig/init/main.c
+++ linux-pm/init/main.c
@@ -613,6 +613,7 @@ asmlinkage void __init start_kernel(void
calibrate_delay();
pidmap_init();
anon_vma_init();
+ acpi_subsystem_init();
#ifdef CONFIG_X86
if (efi_enabled(EFI_RUNTIME_SERVICES))
efi_enter_virtual_mode();
--
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