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From: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	rafael.j.wysocki@intel.com, len.brown@intel.com,
	artem.bityutskiy@linux.intel.com, dave.hansen@linux.intel.com,
	patryk.wlazlyn@linux.intel.com
Subject: [PATCH 0/3] SRF: Fix offline CPU preventing pc6 entry
Date: Thu, 10 Oct 2024 15:39:52 +0200	[thread overview]
Message-ID: <20241010133955.7749-1-patryk.wlazlyn@linux.intel.com> (raw)

The current implementation of the mwait_play_dead() uses undocumented
way of looking up the mwait hint for the deepest cstate and using it in
cpu offline code. This prevents entering pc6 when the CPU gets offlined
on Sierra Forest. The solution is to allow the idle driver to force the
mwait hint.

This problem was first observed on SRF, but since determining the
deepest mwait hint is non-architectural, the hint is forced for all of
the models that intel_idle has custom table for.

Patryk Wlazlyn (3):
  x86/smp: Move mwait hint computation out of mwait_play_dead
  x86/smp: Allow forcing the mwait hint for play dead loop
  intel_idle: Identify the deepest cstate for SRF

 arch/x86/include/asm/smp.h |  3 +++
 arch/x86/kernel/smpboot.c  | 54 ++++++++++++++++++++++++++------------
 drivers/idle/intel_idle.c  | 12 +++++++++
 3 files changed, 52 insertions(+), 17 deletions(-)

-- 
2.46.2


             reply	other threads:[~2024-10-10 13:40 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-10 13:39 Patryk Wlazlyn [this message]
2024-10-10 13:39 ` [PATCH 1/3] x86/smp: Move mwait hint computation out of mwait_play_dead Patryk Wlazlyn
2024-10-10 13:39 ` [PATCH 2/3] x86/smp: Allow forcing the mwait hint for play dead loop Patryk Wlazlyn
2024-10-10 13:39 ` [PATCH 3/3] intel_idle: Identify the deepest cstate for cpu offline code Patryk Wlazlyn

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