Robert Hancock wrote:
I've been looking into why I get these messages on bootup on an Asus
P7P55D PRO motherboard:
Firmware did not grant requested _OSC control
aer 0000:00:03.0:pcie02: AER service couldn't init device: no _OSC support
pci_hotplug: PCI Hot Plug PCI Core version: 0.5
Firmware did not grant requested _OSC control
Firmware did not grant requested _OSC control
Firmware did not grant requested _OSC control
Firmware did not grant requested _OSC control
The AML code for _OSC in the DSDT (below) is almost identical to the
example code in the ACPI spec. From looking at the _OSC method, I don't
see why it should reject any requests for PCI Express hotplug or AER
control.
I can't quite make sense of the ACPI code that is supposed to handle
this. When the AER driver calls acpi_pci_osc_control_set, it first does
this:
/* Need to query controls first before requesting them */
if (!root->osc_queried) {
status = acpi_pci_query_osc(root, root->osc_support_set);
if (ACPI_FAILURE(status))
goto out;
}
Just in case, does removing this 'if' statement fix the problem?
if ((root->osc_control_qry & control_req) != control_req) {
printk(KERN_DEBUG
"Firmware did not grant requested _OSC control\n");
status = AE_SUPPORT;
goto out;
}
Inside acpi_pci_query_osc:
/* do _OSC query for all possible controls */
support_set = root->osc_support_set | (flags & OSC_SUPPORT_MASKS);
capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
capbuf[OSC_SUPPORT_TYPE] = support_set;
capbuf[OSC_CONTROL_TYPE] = OSC_CONTROL_MASKS;
status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
if (ACPI_SUCCESS(status)) {
root->osc_support_set = support_set;
root->osc_control_qry = result;
root->osc_queried = 1;
}
The comment says "do _OSC query for all possible controls", but it
doesn't look like that's what the code is actually doing. The first time
this gets called, assuming osc_support_set is 0, it looks like
support_set passed into _OSC will also be 0. Then osc_queried would be
set to 1, _OSC would never get called again and the cached query result
is based on 0 support flags being passed into _OSC, which is wrong. Or
am I missing something?
Though I might be missing something, I think _OSC is evaluated
and osc_control_qry is updated, whenever acpi_pci_osc_support()
gets called.
Thanks,
Kenji Kaneshige
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