path: root/include/acpi/pdc_intel.h
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* ACPI: Enable bit 11 in _PDC to advertise hw coordPallipadi, Venkatesh2009-02-071-0/+2
| | | | | | | | | | | | | | Bit 11 in intel PDC definitions is meant for OS capability to handle hardware coordination of P-states. In Linux we have always supported hwardware coordination of P-states. Just let the BIOSes know that we support it, by setting this bit. Some BIOSes use this bit to choose between hardware or software coordination and without this change below, BIOSes switch to software coordination, which is not very optimal in terms of power consumption and extra wakeups from idle. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
* ACPI: Processor native C-states using MWAITVenkatesh Pallipadi2006-10-141-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | Intel processors starting with the Core Duo support support processor native C-state using the MWAIT instruction. Refer: Intel Architecture Software Developer's Manual http://www.intel.com/design/Pentium4/manuals/253668.htm Platform firmware exports the support for Native C-state to OS using ACPI _PDC and _CST methods. Refer: Intel Processor Vendor-Specific ACPI: Interface Specification http://www.intel.com/technology/iapc/acpi/downloads/302223.htm With Processor Native C-state, we use 'MWAIT' instruction on the processor to enter different C-states (C1, C2, C3). We won't use the special IO ports to enter C-state and no SMM mode etc required to enter C-state. Overall this will mean better C-state support. One major advantage of using MWAIT for all C-states is, with this and "treat interrupt as break event" feature of MWAIT, we can now get accurate timing for the time spent in C1, C2, .. states. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Len Brown <len.brown@intel.com>
* Enable P-state software coordination via _PDCVenkatesh Pallipadi2006-02-091-0/+5
| | | | | | | http://bugzilla.kernel.org/show_bug.cgi?id=5737 Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
* [ACPI] Avoid BIOS inflicted crashes by evaluating _PDC only onceVenkatesh Pallipadi2005-12-011-3/+1
| | | | | | | | | | | | | | | 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>
* [ACPI] Lindent all ACPI filesLen Brown2005-08-051-3/+1
| | | | Signed-off-by: Len Brown <len.brown@intel.com>
* [ACPI] enable C2 and C3 idle power states on SMPVenkatesh Pallipadi2005-07-121-0/+29
http://bugzilla.kernel.org/show_bug.cgi?id=4401 Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>