a472ad2bce
On ICX platform, the C1E auto-promotion is enabled by default. As a result, the CPU might fall into C1E more offen than previous platforms. Besides, the C1E is not exposed to sysfs on ICX, which is inconsistent with previous server platforms. So disable C1E auto-promotion and expose C1E as a separate idle state, so the C1E and C6 can be disabled via sysfs when necessary. Beside C1 and C1E, the exit latency of C6 was measured by a dedicated tool. However the exit latency(41us) exposed by _CST is much smaller than the one we measured(128us). This is probably due to the _CST uses the exit latency when woken up from PC0+C6, rather than PC6+C6 when C6 was measured. Choose the latter as we need the longest latency in theory. Reported-by: kernel test robot <lkp@intel.com> Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Acked-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Reviewed-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Chen Yu <yu.c.chen@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>