From: Bjorn Helgaas <helgaas@kernel.org>
To: "Limonciello, Mario" <mario.limonciello@amd.com>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
Len Brown <lenb@kernel.org>,
linux-acpi@vger.kernel.org
Subject: Re: [PATCH v4] PCI: Call _REG when transitioning D-states
Date: Fri, 23 Jun 2023 12:35:00 -0500 [thread overview]
Message-ID: <20230623173500.GA180070@bhelgaas> (raw)
In-Reply-To: <03e5d343-848c-02c7-2deb-917d1b93ce8c@amd.com>
On Wed, Jun 21, 2023 at 05:52:52PM -0500, Limonciello, Mario wrote:
> On 6/21/2023 5:28 PM, Bjorn Helgaas wrote:
> > On Tue, Jun 20, 2023 at 09:04:51AM -0500, Mario Limonciello wrote:
> > > Section 6.5.4 of the ACPI 6.4 spec describes how AML is unable to access
> > > an OperationRegion unless `_REG` has been called.
> > > ...
> > > It is reported that ASMedia PCIe GPIO controllers fail
> > > functional tests after the system has returning from suspend (S3
> > > or s2idle). This is because the BIOS checks whether the OSPM has
> > > called the `_REG` method to determine whether it can interact
> > > with the OperationRegion assigned to the device as part of the
> > > other AML called for the device.
> I double checked a BIOS debug log which shows ACPI calls
> to confirm and didn't see a single _REG call for any device
> before this patch across a boot/suspend/resume cycle.
Sorry to follow up on this again.
The commit log says these GPIO controllers fail functional tests after
returning from suspend. Do those functional tests pass *before*
suspend? If so, why?
Without this patch, we *never* call _REG, so the fact that calling
_REG when we return the device to D0 while resuming fixes something
suggests that it might have been broken even before the suspend.
Bjorn
next prev parent reply other threads:[~2023-06-23 17:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-20 14:04 [PATCH v4] PCI: Call _REG when transitioning D-states Mario Limonciello
2023-06-21 11:25 ` Rafael J. Wysocki
2023-06-21 22:28 ` Bjorn Helgaas
2023-06-21 22:52 ` Limonciello, Mario
2023-06-22 17:43 ` Limonciello, Mario
2023-06-22 22:08 ` Bjorn Helgaas
2023-06-22 22:10 ` Bjorn Helgaas
2023-06-23 17:35 ` Bjorn Helgaas [this message]
2023-06-23 18:08 ` Limonciello, Mario
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