#ifndef _UAPI_LINUX_REBOOT_H #define _UAPI_LINUX_REBOOT_H /* * Magic values required to use _reboot() system call. */ #define LINUX_REBOOT_MAGIC1 0xfee1dead #define LINUX_REBOOT_MAGIC2 672274793 #define LINUX_REBOOT_MAGIC2A 85072278 #define LINUX_REBOOT_MAGIC2B 369367448 #define LINUX_REBOOT_MAGIC2C 537993216 /* * Commands accepted by the _reboot() system call. * * RESTART Restart system using default command and mode. * HALT Stop OS and give system control to ROM monitor, if any. * CAD_ON Ctrl-Alt-Del sequence causes RESTART command. * CAD_OFF Ctrl-Alt-Del sequence sends SIGINT to init task. * POWER_OFF Stop OS and remove all power from system, if possible. * RESTART2 Restart system using given command string. * SW_SUSPEND Suspend system using software suspend if compiled in. * KEXEC Restart system using a previously loaded Linux kernel */ #define LINUX_REBOOT_CMD_RESTART 0x01234567 #define LINUX_REBOOT_CMD_HALT 0xCDEF0123 #define LINUX_REBOOT_CMD_CAD_ON 0x89ABCDEF #define LINUX_REBOOT_CMD_CAD_OFF 0x00000000 #define LINUX_REBOOT_CMD_POWER_OFF 0x4321FEDC #define LINUX_REBOOT_CMD_RESTART2 0xA1B2C3D4 #define LINUX_REBOOT_CMD_SW_SUSPEND 0xD000FCE2 #define LINUX_REBOOT_CMD_KEXEC 0x45584543 #endif /* _UAPI_LINUX_REBOOT_H */ k net-next plumbingsTobias Klauser
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authorSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>2017-02-03 14:18:39 -0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-02-04 00:11:08 +0100
commit6e978b22efa1db9f6e71b24440b5f1d93e968ee3 (patch)
treec666f7a26b860674848949e39a610222b0723f89 /include/xen/xen-ops.h
parent3c223c19aea85d3dda1416c187915f4a30b04b1f (diff)
cpufreq: intel_pstate: Disable energy efficiency optimization
Some Kabylake desktop processors may not reach max turbo when running in HWP mode, even if running under sustained 100% utilization. This occurs when the HWP.EPP (Energy Performance Preference) is set to "balance_power" (0x80) -- the default on most systems. It occurs because the platform BIOS may erroneously enable an energy-efficiency setting -- MSR_IA32_POWER_CTL BIT-EE, which is not recommended to be enabled on this SKU. On the failing systems, this BIOS issue was not discovered when the desktop motherboard was tested with Windows, because the BIOS also neglects to provide the ACPI/CPPC table, that Windows requires to enable HWP, and so Windows runs in legacy P-state mode, where this setting has no effect. Linux' intel_pstate driver does not require ACPI/CPPC to enable HWP, and so it runs in HWP mode, exposing this incorrect BIOS configuration. There are several ways to address this problem. First, Linux can also run in legacy P-state mode on this system. As intel_pstate is how Linux enables HWP, booting with "intel_pstate=disable" will run in acpi-cpufreq/ondemand legacy p-state mode. Or second, the "performance" governor can be used with intel_pstate, which will modify HWP.EPP to 0. Or third, starting in 4.10, the /sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference attribute in can be updated from "balance_power" to "performance". Or fourth, apply this patch, which fixes the erroneous setting of MSR_IA32_POWER_CTL BIT_EE on this model, allowing the default configuration to function as designed. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Reviewed-by: Len Brown <len.brown@intel.com> Cc: 4.6+ <stable@vger.kernel.org> # 4.6+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include/xen/xen-ops.h')