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Message-ID: <106803fab8da4648a6881991c7f37214@AcuMS.aculab.com>
Date: Fri, 18 Aug 2023 08:21:49 +0000
From: David Laight <David.Laight@...LAB.COM>
To: "'Rafael J. Wysocki'" <rafael@...nel.org>,
Mario Limonciello <mario.limonciello@....com>
CC: Mika Westerberg <mika.westerberg@...ux.intel.com>,
Bjorn Helgaas <helgaas@...nel.org>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@...ux.intel.com>,
Iain Lane <iain@...ngesquash.org.uk>,
Shyam-sundar S-k <Shyam-sundar.S-k@....com>,
"stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: RE: [PATCH v13 01/12] PCI: Only put Intel PCIe ports >= 2015 into D3
From: Rafael J. Wysocki
> Sent: Friday, August 18, 2023 9:12 AM
>
> On Fri, Aug 18, 2023 at 7:14 AM Mario Limonciello
> <mario.limonciello@....com> wrote:
> >
> > commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
> > changed pci_bridge_d3_possible() so that any vendor's PCIe ports
> > from modern machines (>=2015) are allowed to be put into D3.
> >
> > Iain reports that USB devices can't be used to wake a Lenovo Z13
> > from suspend. This is because the PCIe root port has been put
> > into D3 and AMD's platform can't handle USB devices waking in this
> > case.
> >
...
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 60230da957e0c..051e88ee64c63 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -3037,10 +3037,11 @@ bool pci_bridge_d3_possible(struct pci_dev *bridge)
> > return false;
> >
> > /*
> > - * It should be safe to put PCIe ports from 2015 or newer
> > + * It is safe to put Intel PCIe ports from 2015 or newer
> > * to D3.
> > */
>
> I would say "Allow Intel PCIe ports from 2015 onward to go into D3 to
> achieve additional energy conservation on some platforms" without the
> "It is safe" part that is kind of obvious (it wouldn't be done if it
> were unsafe).
Just say why...
"Don't put root ports into D3 on non-Intel systems to avoid issues
with USB devices being unable to wake up some AMD based laptops."
David
-
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