From: Bjorn Helgaas <helgaas@kernel.org>
To: linux-pci@vger.kernel.org
Cc: "David E. Box" <david.e.box@linux.intel.com>,
Jonathan Yong <jonathan.yong@intel.com>,
Len Brown <lenb@kernel.org>
Subject: [bugzilla-daemon@bugzilla.kernel.org: [Bug 209361] New: PTMControl Enabled blocks Low Power Idle in 5% of s2idle attempts - Dell XPS-13 9300 Ice Lake]
Date: Wed, 23 Sep 2020 14:00:45 -0500 [thread overview]
Message-ID: <20200923190045.GA2285394@bjorn-Precision-5520> (raw)
----- Forwarded message from bugzilla-daemon@bugzilla.kernel.org -----
Date: Wed, 23 Sep 2020 15:22:47 +0000
From: bugzilla-daemon@bugzilla.kernel.org
To: bjorn@helgaas.com
Subject: [Bug 209361] New: PTMControl Enabled blocks Low Power Idle in 5% of
s2idle attempts - Dell XPS-13 9300 Ice Lake
Message-ID: <bug-209361-41252@https.bugzilla.kernel.org/>
https://bugzilla.kernel.org/show_bug.cgi?id=209361
Bug ID: 209361
Summary: PTMControl Enabled blocks Low Power Idle in 5% of
s2idle attempts - Dell XPS-13 9300 Ice Lake
Product: Drivers
Version: 2.5
Kernel Version: 5.9-rc5
Hardware: All
OS: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: PCI
Assignee: drivers_pci@kernel-bugs.osdl.org
Reporter: lenb@kernel.org
Regression: No
System: Dell XPS-13 9300, Intel(R) Core(TM) i7-1065G7
Up through Linux 5.9-rc5, this system will typically get very good residency
in Low-Power-Idle upon s2idle. But on 5% of attempts, it gets ZERO
residency in low-power-idle.
I have confirmed that this does not change if the time sleeping
is extended, or the time between experiments is extended.
David Box suggested disabling PTM.
Doing so resulted -- for the first time --
the system entering LPI on s2idle 100% of s2idle attempts
(770 attempts over 8 hours)
~/bin/pci_write8 0 0x1d 0 0x158 0
~/bin/pci_write8 0 0x1d 7 0x158 0
is what I used to disable PTM on my system
(write a 0, where pci_read8 previously showed the value 3)
This change is visible in the output of lspci as for both bridges:
< PTMControl: Enabled:+ RootSelected:+
> PTMControl: Enabled:- RootSelected:-
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reply other threads:[~2020-09-23 19:00 UTC|newest]
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