Re: [PATCH v8 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

Kuppuswamy, Sathyanarayanan
2020-09-16T02:33:48Z

On 9/15/20 3:20 PM, Bjorn Helgaas wrote:
> On Sun, Sep 13, 2020 at 01:54:38PM -0700, Kuppuswamy, Sathyanarayanan wrote:
>> On 9/10/20 1:14 PM, Bjorn Helgaas wrote:
>>> On Fri, Jul 24, 2020 at 08:58:53PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
>>>> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>>>>
>>>> pcie_ports_native is set only if user requests native handling
>>>> of PCIe capabilities via pcie_port_setup command line option.
>>>> User input takes precedence over _OSC based control negotiation
>>>> result. So consider the _OSC negotiated result only if
>>>> pcie_ports_native is unset.
>>>>
>>>> Also, since struct pci_host_bridge ->native_* members caches the
>>>> ownership status of various PCIe capabilities, use them instead
>>>> of distributed checks for pcie_ports_native.
>>>>
>>>> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>>>> ---
>>>> drivers/acpi/pci_root.c | 61 ++++++++++++++++++++++++++-----
>>>> drivers/pci/hotplug/pciehp_core.c | 2 +-
>>>> drivers/pci/pci-acpi.c | 3 --
>>>> drivers/pci/pcie/aer.c | 2 +-
>>>> drivers/pci/pcie/portdrv_core.c | 9 ++---
>>>> 5 files changed, 56 insertions(+), 21 deletions(-)
>>>>
>>>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>>>> index f90e841c59f5..f8981d4e044d 100644
>>>> --- a/drivers/acpi/pci_root.c
>>>> +++ b/drivers/acpi/pci_root.c
>>>> @@ -145,6 +145,17 @@ static struct pci_osc_bit_struct pci_osc_control_bit[] = {
>>>> { OSC_PCI_EXPRESS_DPC_CONTROL, "DPC" },
>>>> };
>>
>>>> + else
>>>> + dev_warn(&bus->dev, "OS overrides %s firmware control",
>>>> + get_osc_desc(OSC_PCI_EXPRESS_NATIVE_HP_CONTROL));
>>>
>>> There's got to be a way to write this more concisely. Maybe something
>>> like this?
>>>
>>> #define OSC_OWNER(ctrl, bit, flag) \
>>> if (!(ctrl & bit)) \
>>> flag = 0;
>>>
>>> if (pcie_ports_native)
>>> decode_osc_control(root, "OS forcibly taking over", ~0);
>>
>> BIT1 and BIT6 does not have PCIe dependency. And BIT7-31 are reserved.
>> So we can't force all _OSC bits based on pcie_ports_native value.
>> So, IM0, its better to handle PCIe features seperatly.
>
> Yes, we may need to handle a few bits specially. But we need to
> figure out a nicer-looking way of coding this. It's too cumbersome to
> check pcie_ports_native and log a message for every _OSC bit
> individually.
ok. Let me check how to simplify it.
>
>>> else {
>>> ctrl = root->osc_control_set;
>>> OSC_OWNER(ctrl, OSC_PCI_EXPRESS_AER_CONTROL, host_bridge->native_aer);
>>> OSC_OWNER(ctrl, OSC_PCI_EXPRESS_PME_CONTROL, host_bridge->native_pme);
>>> ...
>>> }
>>
>>
>> --
>> Sathyanarayanan Kuppuswamy
>> Linux Kernel Developer

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer