On 6/23/2023 12:35 PM, Bjorn Helgaas wrote:
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
The reason it works is because the only time the AML attempts
to access the config space is part of suspend/resume. If it
attempted to access config space as part of startup then I'd
expect the same failure at startup.
