Commit c4e1acbb authored Mar 13, 2014 by Rafael J. Wysocki

ACPI / init: Invoke early ACPI initialization later

Commit 73f7d1ca (ACPI / init: Run acpi_early_init() before
timekeeping_init()) optimistically moved the early ACPI initialization
before timekeeping_init(), but that didn't work, because it broke fast
TSC calibration for Julian Wollrath on Thinkpad x121e (and most likely
for others too). The reason is that acpi_early_init() enables the SCI
and that interferes with the fast TSC calibration mechanism.

Thus follow the original idea to execute acpi_early_init() before
efi_enter_virtual_mode() to help the EFI people for now and we can
revisit the other problem that commit 73f7d1ca attempted to
address in the future (if really necessary).

Fixes: 73f7d1ca (ACPI / init: Run acpi_early_init() before timekeeping_init())
Reported-by: Julian Wollrath <jwollrath@web.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent fa389e22

init/main.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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();
		@@ -613,6 +612,7 @@ asmlinkage void __init start_kernel(void)
		calibrate_delay();
		pidmap_init();
		anon_vma_init();
		acpi_early_init();
		#ifdef CONFIG_X86
		if (efi_enabled(EFI_RUNTIME_SERVICES))
		efi_enter_virtual_mode();

Admin message