On 09/14/2017 11:11 AM, Bjorn Helgaas wrote:
> [+cc linux-pci]
>
> On Thu, Sep 14, 2017 at 12:00 PM, Jens Axboe <axboe@xxxxxxxxx> wrote:
>> On 09/12/2017 02:04 PM, Johannes Berg wrote:
>>> On Tue, 2017-09-12 at 13:43 -0600, Jens Axboe wrote:
>>>
>>>> CC'ing the guilty part and Bjorn. I'm assuming it's the
>>>> pci_is_enabled() check, since the rest of the patch shouldn't have
>>>> functional changes.
>>>
>>> and pci_enable_bridge() already checks if it's already enabled, but
>>> still enables mastering in that case if it isn't:
>>>
>>> static void pci_enable_bridge(struct pci_dev *dev)
>>> {
>>> [...]
>>> if (pci_is_enabled(dev)) {
>>> if (!dev->is_busmaster)
>>> pci_set_master(dev);
>>> return;
>>> }
>>>
>>> so I guess due to the new check we end up with mastering disabled, and
>>> thus the firmware can't load since that's a DMA thing?
>>
>> Bjorn/Srinath, any input here? This is a regression that prevents wifi
>> from working on a pretty standard laptop. It'd suck to have this be in
>> -rc1. Seems like the trivial fix would be:
>>
>>
>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>> index b0002daa50f3..ffbe11dbdd61 100644
>> --- a/drivers/pci/pci.c
>> +++ b/drivers/pci/pci.c
>> @@ -1394,7 +1394,7 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags)
>> return 0; /* already enabled */
>>
>> bridge = pci_upstream_bridge(dev);
>> - if (bridge && !pci_is_enabled(bridge))
>> + if (bridge)
>> pci_enable_bridge(bridge);
>>
>> /* only skip sriov related */
>>
>>
>
> Looks like a reasonable fix. I assume it works for you? I don't have
> a way to test it, so if you can verify that it works and supply a
> Signed-off-by, I can merge it.
Booting it right now, I'll send out a proper version in a few minutes.
--
Jens Axboe
