linux/drivers/cpuidle
Venkatesh Pallipadi dcb84f335b cpuidle acpi driver: fix oops on AC<->DC
cpuidle and acpi driver interaction bug with the way cpuidle_register_driver()
is called. Due to this bug, there will be oops on
AC<->DC on some systems, where they support C-states in one DC and not in AC.

The current code does
ON BOOT:
	Look at CST and other C-state info to see whether more than C1 is
	supported. If it is, then acpi processor_idle does a
	cpuidle_register_driver() call, which internally enables the device.

ON CST change notification (AC<->DC) and on suspend-resume:
	acpi driver temporarily disables device, updates the device with
	any new C-states, and reenables the device.

The problem is is on boot, there are no C2, C3 states supported and we skip
the register. Later on AC<->DC, we may get a CST notification and we try
to reevaluate CST and enabled the device, without actually registering it.
This causes breakage as we try to create /sys fs sub directory, without the
parent directory which is created at register time.

Thanks to Sanjeev for reporting the problem here.
http://bugzilla.kernel.org/show_bug.cgi?id=10394

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2008-06-11 19:13:45 -04:00
..
governors pm qos infrastructure and interface 2008-02-05 09:44:22 -08:00
cpuidle.c cpuidle acpi driver: fix oops on AC<->DC 2008-06-11 19:13:45 -04:00
cpuidle.h
driver.c
governor.c cpuidle: remove unused exports 2007-10-29 17:27:50 -04:00
Kconfig ACPI: CONFIG_CPU_IDLE=ACPI by default 2007-11-19 22:22:37 -05:00
Makefile
sysfs.c cpuidle: fix cpuidle time and usage overflow 2008-03-26 00:45:26 -04:00