Public bug reported:
[Impact]
On some platforms, aggressive C1 auto-demotion may lead to failure to enter
the deepest C-state during suspend-to-idle, causing high power consumption.
To prevent this, disable C1 auto-demotion during suspend and re-enable on
resume.
[Fix]
Below 2 commits in linux-next fix the issue
7a797cc9f809 platform/x86/intel/pmc: Disable C1 auto-demotion during suspend
9fe43c8020a6 platform/x86/intel/pmc: Refactor platform resume functions to use
cnl_resume()
[Test]
Connect the power meter on the machine(MTL/ARL/LNL) and run s2idle tests
multiple times,
it should consume ~0.5w during s2idle.
[Where problems could occur]
It's hard to tell what could cause changes to the CPU flags.
So, only submit this to OEM kernel.
** Affects: hwe-next
Importance: Undecided
Status: New
** Affects: linux-oem-6.11 (Ubuntu)
Importance: Undecided
Status: Invalid
** Affects: linux-oem-6.11 (Ubuntu Noble)
Importance: Undecided
Assignee: AceLan Kao (acelankao)
Status: In Progress
** Tags: jira-wtn-10 oem-priority
** Also affects: linux-oem-6.11 (Ubuntu Noble)
Importance: Undecided
Status: New
** Changed in: linux-oem-6.11 (Ubuntu Noble)
Status: New => In Progress
** Changed in: linux-oem-6.11 (Ubuntu Noble)
Assignee: (unassigned) => AceLan Kao (acelankao)
** Changed in: linux-oem-6.11 (Ubuntu)
Status: New => Invalid
** Tags added: jira-wtn-10 oem-priority
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https://bugs.launchpad.net/bugs/2088964
Title:
Disable C1 auto-demotion during suspend for MTL/ARL/LNL platforms
Status in HWE Next:
New
Status in linux-oem-6.11 package in Ubuntu:
Invalid
Status in linux-oem-6.11 source package in Noble:
In Progress
Bug description:
[Impact]
On some platforms, aggressive C1 auto-demotion may lead to failure to enter
the deepest C-state during suspend-to-idle, causing high power consumption.
To prevent this, disable C1 auto-demotion during suspend and re-enable on
resume.
[Fix]
Below 2 commits in linux-next fix the issue
7a797cc9f809 platform/x86/intel/pmc: Disable C1 auto-demotion during suspend
9fe43c8020a6 platform/x86/intel/pmc: Refactor platform resume functions to
use cnl_resume()
[Test]
Connect the power meter on the machine(MTL/ARL/LNL) and run s2idle tests
multiple times,
it should consume ~0.5w during s2idle.
[Where problems could occur]
It's hard to tell what could cause changes to the CPU flags.
So, only submit this to OEM kernel.
To manage notifications about this bug go to:
https://bugs.launchpad.net/hwe-next/+bug/2088964/+subscriptions
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