On Mon, Dec 7, 2009 at 3:26 AM, Kenji Kaneshige
<kaneshige.kenji@xxxxxxxxxxxxxx> wrote:
> 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.
Ahh, I missed that acpi_pci_query_osc is also called from acpi_pci_osc_support.
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