On Wed, Jul 30, 2014 at 4:13 PM, Yijing Wang <wangyijing@xxxxxxxxxx> wrote:
>>> Yes, that issue is BIOS bug, the mps setting is wrong after system boot up.
>>> But that issue is not same as this one, Keith and Jordan found the issue
>>> after hot-plug. And my patch only modify the hotplug slot connected device.
>>>
>>> In my idea, make the device work is important, because these platforms with windows
>>> can run happy, why linux leave this issue to BIOS.
>>
>> That is a reason to make it works with Linux, but does your
>> platform have _HPX from ACPI for those hot-added back devices ? if it
>> has, maybe windows could apply _HPX to configure those devices and
>> work well.
>>
>
> I checked DSDT table exported from my server, but no "_HPX" found.
You might check the wrong place...
> Further more, kernel use pciehp first to support pcie hotplug device. And in pciehp,
> driver won't touch ACPI methods like "_HPX".
That is not true, please read the code in pciehp_pci.c
pciehp_configure_device()
pci_configure_slot()
pci_get_hp_params()
acpi_run_hpx()
acpi_evaluate_object(handle, "_HPX",...)
...
Native pciehp also does acpi parameter importing ... ...
Thank,s
Ethan
>
> Thanks!
> Yijing.
>
>>>
>>>>
>>>>> Reported-by: Keith Busch <keith.busch@xxxxxxxxx>
>>>>> Reported-by: Jordan_Hargrave@xxxxxxxx
>>>>> Reported-by: Yijing Wang <wangyijing@xxxxxxxxxx>
>>>>> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
>>>>> Cc: Jon Mason <jdmason@xxxxxxxx>
>>>>> ---
>>>>> drivers/pci/probe.c | 39 +++++++++++++++++++++++++++++++++++++++
>>>>> 1 files changed, 39 insertions(+), 0 deletions(-)
>>>>>
>>>>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>>>>> index e3cf8a2..583ca52 100644
>>>>> --- a/drivers/pci/probe.c
>>>>> +++ b/drivers/pci/probe.c
>>>>> @@ -1613,6 +1613,44 @@ static void pcie_write_mrrs(struct pci_dev *dev)
>>>>> dev_err(&dev->dev, "MRRS was unable to be configured with a safe value. If problems are experienced, try running with pci=pcie_bus_safe\n");
>>>>> }
>>>>>
>>>>> +/**
>>>>> + * pcie_bus_update_set - update device mps when device doing hot-add
>>>>> + * @dev: PCI device to set
>>>>> + *
>>>>> + * After device hot add, mps will be set to default(128B), But the
>>>>> + * upstream port device's mps may be larger than 128B which was set
>>>>> + * by firmware during system bootup. Then we should update the device
>>>>> + * mps to equal to its parent mps, Or the device can not work normally.
>>>>> + */
>>>>> +static void pcie_bus_update_set(struct pci_dev *dev)
>>>>> +{
>>>>> + int mps, p_mps, mpss;
>>>>> + struct pci_dev *parent;
>>>>> +
>>>>> + if (!pci_is_pcie(dev) || !dev->bus->self
>>>>> + || !dev->bus->self->is_hotplug_bridge)
>>>>> + return;
>>>>> +
>>>>> + parent = dev->bus->self;
>>>>> + mps = pcie_get_mps(dev);
>>>>> + p_mps = pcie_get_mps(parent);
>>>>> +
>>>>> + if (mps >= p_mps)
>>>>> + return;
>>>>> +
>>>>> + mpss = 128 << dev->pcie_mpss;
>>>>> + if (mpss < p_mps) {
>>>>> + dev_warn(&dev->dev, "MPSS %d smaller than upstream MPS %d\n"
>>>>> + "If necessary, use \"pci=pcie_bus_safe\" boot parameter to avoid this problem\n",
>>>>> + mpss, p_mps);
>>>>> + return;
>>>>> + }
>>>>> +
>>>>> + pcie_write_mps(dev, p_mps);
>>>>> + dev_info(&dev->dev, "Max Payload Size set to %4d/%4d (was %4d)\n",
>>>>> + pcie_get_mps(dev), 128 << dev->pcie_mpss, mps);
>>>>> +}
>>>>> +
>>>>> static void pcie_bus_detect_mps(struct pci_dev *dev)
>>>>> {
>>>>> struct pci_dev *bridge = dev->bus->self;
>>>>> @@ -1637,6 +1675,7 @@ static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
>>>>> return 0;
>>>>>
>>>>> if (pcie_bus_config == PCIE_BUS_TUNE_OFF) {
>>>>> + pcie_bus_update_set(dev);
>>>>> pcie_bus_detect_mps(dev);
>>>>> return 0;
>>>>> }
>>>>> --
>>>>> 1.7.1
>>>>>
>>>>> --
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>>>>
>>>> .
>>>>
>>>
>>>
>>> --
>>> Thanks!
>>> Yijing
>>>
>>
>> .
>>
>
>
> --
> Thanks!
> Yijing
>
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