The core cpufreq code doesn't appear to understand returning -EAGAIN
for the get() function of the cpufreq_driver. If PAL_GET_PSTATE returns
-1, such as when running on Xen, scaling_cur_freq is happy to return
4294967285 kHz (ie. (unsigned)-11). The other drivers appear to return
0 for a failure, and doing so gives me the max frequency from
scaling_cur_frequency and "<unknown>" from cpuinfo_cur_frequency. I
believe that's the desired behavior.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
PAL_GET_PSTATE accepts a type argument to return different kinds of
frequency information.
Refer: Intel Itanium®Architecture Software Developer's Manual -
Volume 2: System Architecture, Revision 2.2
(http://developer.intel.com/design/itanium/manuals/245318.htm)
Add the support for type argument and use Instantaneous frequency
in the acpi driver.
Also fix a bug, where in return value of PAL_GET_PSTATE was getting compared
with 'control' bits instead of 'status' bits.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
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>
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>
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>
Alex Williamson