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authorZhang Rui <rui.zhang@intel.com>2022-04-15 17:39:51 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-04-28 14:50:09 +0200
commitd1cf8bbfed1edc5108220342ab39e4544d55fbc3 (patch)
tree63c5edc0713f5445102ab424db027fd0da7b8d7c /drivers/cpuidle
parent7eac3bd38d18cd3317756649921b8264ddfee692 (diff)
intel_idle: Add AlderLake support
Similar to SPR, the C1 and C1E states on ADL are mutually exclusive. Only one of them can be enabled at a time. But contrast to SPR, which usually has a strong latency requirement as a Xeon processor, C1E is preferred on ADL for better energy efficiency. Add custom C-state tables for ADL with both C1 and C1E, and 1. Enable the "C1E promotion" bit in MSR_IA32_POWER_CTL and mark C1 with the CPUIDLE_FLAG_UNUSABLE flag, so C1 is not available by default. 2. Add support for the "preferred_cstates" module parameter, so that users can choose to use C1 instead of C1E by booting with "intel_idle.preferred_cstates=2". Separate custom C-state tables are introduced for the ADL mobile and desktop processors, because of the exit latency differences between these two variants, especially with respect to PC10. Signed-off-by: Zhang Rui <rui.zhang@intel.com> [ rjw: Changelog edits, code rearrangement ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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