(2010/08/04 6:02), Rafael J. Wysocki wrote:
> On Tuesday, August 03, 2010, Rafael J. Wysocki wrote:
>> On Tuesday, August 03, 2010, Hidetoshi Seto wrote:
>>> (2010/08/03 13:52), Kenji Kaneshige wrote:
>>>> (2010/08/03 6:59), Rafael J. Wysocki wrote:
>>>>> @@ -434,19 +432,6 @@ acpi_status acpi_pci_osc_control_set(acp
>>>>> if ((root->osc_control_set& control_req) == control_req)
>>>>> goto out;
>>>>>
>>>>> - /* Need to query controls first before requesting them */
>>>>> - if (!root->osc_queried) {
>>>>> - status = acpi_pci_query_osc(root, root->osc_support_set, NULL);
>>>>> - 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;
>>>>> - }
>>>>
>>>> I think acpi_pci_osc_control_set() still need to query before commit
>>>> to ensure all the requested controls are granted to OS.
>>>>
>>>> So the code needs to be
>>>>
>>>> status = acpi_pci_query_osc(root, root->osc_support_set,&control_req);
>>>> if (ACPI_FAILURE(status))
>>>> goto out;
>>>
Sorry, that should have been
query = control_req;
status = acpi_pci_query_osc(root, root->osc_support_set, &query);
if (ACPI_FAILURE(status))
goto out;
if ((query & control_req) != control_req) {
printk_(KERN_DEBUG
"Firmware did not grant requested _OSC control\n");
status = AE_SUPPORT;
goto out;
}
I know current pcie_port_acpi_setup() queries the requesting controls
before acpi_pci_osc_control_set() and only one control is requested
in the other code. However, I think acpi_pci_osc_control_set() still
need to query the requested controls to ensure all the requested
controls, in case someone calls this function without querying the
requesting controls. In other words, I think it must be ensured that
any controls are never granted to OS when acpi_pci_osc_control_set()
returns error.
>>>> status = acpi_pci_query_osc(root, root->osc_support_set,&control_req);
>>>> if (ACPI_FAILURE(status))
>>>> goto out;
By the way, I think it is getting confusing regarding who query the
controls. IMO, querying controls to ensure all the requested controls
are granted to OS should be done in acpi_pci_osc_control_set(), as
I said above. On the other hand, PCIe port driver need to query
controls for other reason... Now I think it might be better to change
acpi_pci_osc_control_set() like below instead of introducing
acpi_pci_osc_control_query().
acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *flags)
{
...
query = control_req;
status = acpi_pci_query_osc(root, root->osc_support_set, &query);
if (ACPI_FAILURE(status))
goto out;
if ((query & control_req) != control_req) {
printk_(KERN_DEBUG
"Firmware did not grant requested _OSC control\n");
status = AE_SUPPORT;
*flags = (query & control_req);
goto out;
}
...
}
And do as follows in pcie_port_acpi_setup()
status = acpi_pci_osc_control_set(handle, &flags);
if (status == AE_SUPPORT) {
/* 2nd try */
status = acpi_pci_osc_control_set(handle, &flags);
}
if (ACPI_FAILURE(status)) {
...
What do you think about this?
Thanks,
Kenji Kaneshige
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