Commit Graph

3 Commits

Author SHA1 Message Date
Venkatesh Pallipadi c82e6abfb3 [ACPI] IA64 ZX1 buildfix for _PDC patch
http://bugzilla.kernel.org/show_bug.cgi?id=5483

ZX1 config doesn't include cpufreq, so move move acpi-processor.c
up out of ia64/cpufreq directory.

no functional changes

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2005-12-05 17:24:45 -05:00
Venkatesh Pallipadi 05131ecc99 [ACPI] Avoid BIOS inflicted crashes by evaluating _PDC only once
Linux invokes the AML _PDC method (Processor Driver Capabilities)
to tell the BIOS what features it can handle.  While the ACPI
spec says nothing about the OS invoking _PDC multiple times,
doing so with changing bits seems to hopelessly confuse the BIOS
on multiple platforms up to and including crashing the system.

Factor out the _PDC invocation so Linux invokes it only once.

http://bugzilla.kernel.org/show_bug.cgi?id=5483

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2005-12-01 01:30:35 -05:00
Venkatesh Pallipadi 4db8699bcf [IA64] Add ACPI based P-state support
Patch to support P-state transitions on ia64. This driver is based on ACPI,
and uses the ACPI processor driver interface to find out the P-state support
information for the processor. This driver plugs into generic cpufreq
infrastructure.

Once this driver is loaded successfully, ondemand/userspace governor can be
used to change the CPU frequency dynamically based on load or on request from
userspace process.

Refer :
ACPI specification -
      http://www.acpi.info
P-state related PAL calls -
      http://developer.intel.com/design/itanium/downloads/24869909.pdf

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2005-08-26 15:09:24 -07:00