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From: Bjorn Helgaas <helgaas@kernel.org>
To: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Thomas Witt <thomas@witt.link>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Kuppuswamy Sathyanarayanan 
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	Vidya Sagar <vidyas@nvidia.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Kai-Heng Feng <kai.heng.feng@canonical.com>,
	Michael Bottini <michael.a.bottini@linux.intel.com>,
	"David E . Box" <david.e.box@linux.intel.com>,
	Tasev Nikola <tasev.stefanoska@skynet.be>,
	Mark Enriquez <enriquezmark36@gmail.com>,
	Thomas Witt <kernel@witt.link>, Koba Ko <koba.ko@canonical.com>,
	linux-pci@vger.kernel.org
Subject: Re: [PATCH] PCI/ASPM: Add back L1 PM Substate save and restore
Date: Tue, 27 Jun 2023 15:41:24 -0500	[thread overview]
Message-ID: <20230627204124.GA366188@bhelgaas> (raw)
In-Reply-To: <20230627100447.GC14638@black.fi.intel.com>

On Tue, Jun 27, 2023 at 01:04:47PM +0300, Mika Westerberg wrote:
> On Tue, Jun 27, 2023 at 11:53:33AM +0200, Thomas Witt wrote:
> > On 27/06/2023 08:24, Mika Westerberg wrote:
> > > Commit a7152be79b62 ("Revert "PCI/ASPM: Save L1 PM Substates Capability
> > > for suspend/resume"") reverted saving and restoring of ASPM L1 Substates
> > > due to a regression that caused resume from suspend to fail on certain
> > > systems. However, we never added this capability back and this is now
> > > causing systems fail to enter low power CPU states, drawing more power
> > > from the battery.
> > 
> > Hello Mika,
> > 
> > I am sorry, but your patch (applied on top of master) triggers the exact
> > same behaviour I described in
> > <https://bugzilla.kernel.org/show_bug.cgi?id=216877> (nvme and wifi become
> > unavailable during suspend/resume)
> 
> Thanks for testing! Can you provide the output of dmidecode from that
> system? We can add it to the denylist as well to avoid the issue on your
> system.

To me this says we don't completely understand the mechanism of the
failure.  If BIOS made L1SS work initially, Linux should be able to
make it work again after suspend/resume.

If we can identify an actual hardware or firmware defect, it makes
good sense to add a quirk or denylist.  But I'll push back a little if
it's just "there's some problem we don't understand on this system, so
avoid it."

Bjorn

  reply	other threads:[~2023-06-27 20:41 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-27  6:24 [PATCH] PCI/ASPM: Add back L1 PM Substate save and restore Mika Westerberg
2023-06-27  9:53 ` Thomas Witt
2023-06-27 10:04   ` Mika Westerberg
2023-06-27 20:41     ` Bjorn Helgaas [this message]
2023-06-28  6:46       ` Mika Westerberg
2023-06-28 10:24         ` Thomas Witt
2023-06-28 10:59           ` Mika Westerberg
2023-06-28 12:30             ` Mika Westerberg
2023-06-29  9:47             ` Thomas Witt
2023-06-29 10:23               ` Mika Westerberg
2023-06-29 14:24               ` David E. Box
2023-06-30 10:41                 ` Mika Westerberg
2023-06-30 16:58                   ` Thomas Witt
2023-07-05 20:53                     ` David E. Box
2023-07-06 19:14                       ` Thomas Witt
2023-07-31 15:01                         ` Mika Westerberg
2023-08-05  7:57                           ` Thomas Witt
2023-08-07  7:58                             ` Mika Westerberg
2023-08-10 23:44                               ` David E. Box
2023-06-28 12:16         ` Mario Limonciello
2023-06-28 12:38           ` Mika Westerberg

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