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;
}
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?
Name (PEHP, One)
Name (SHPC, Zero)
Name (PEPM, One)
Name (PEER, One)
Name (PECS, One)
...
Method (_OSC, 4, NotSerialized)
{
Name (SUPP, Zero)
Name (CTRL, Zero)
CreateDWordField (Arg3, Zero, CDW1)
CreateDWordField (Arg3, 0x04, CDW2)
CreateDWordField (Arg3, 0x08, CDW3)
If (LEqual (Arg0, Buffer (0x10)
{
/* 0000 */ 0x5B, 0x4D, 0xDB, 0x33, 0xF7,
0x1F, 0x1C, 0x40,
/* 0008 */ 0x96, 0x57, 0x74, 0x41, 0xC0,
0x3D, 0xD7, 0x66
}))
{
Store (CDW2, SUPP)
Store (CDW3, CTRL)
If (LNotEqual (And (SUPP, 0x16), 0x16))
{
And (CTRL, 0x1E, CTRL)
}
If (LNot (PEHP))
{
And (CTRL, 0x1E, CTRL)
}
If (LNot (SHPC))
{
And (CTRL, 0x1D, CTRL)
}
If (LNot (PEPM))
{
And (CTRL, 0x1B, CTRL)
}
If (LNot (PEER))
{
And (CTRL, 0x15, CTRL)
}
If (LNot (PECS))
{
And (CTRL, 0x0F, CTRL)
}
If (Not (And (CDW1, One)))
{
If (And (CTRL, One)) {}
If (And (CTRL, 0x04)) {}
If (And (CTRL, 0x10)) {}
}
If (LNotEqual (Arg1, One))
{
Or (CDW1, 0x08, CDW1)
}
If (LNotEqual (CDW3, CTRL))
{
Or (CDW1, 0x10, CDW1)
}
And (CTRL, 0xEF, CTRL)
Store (CTRL, CDW3)
