[+cc linux-pci]
On Thu, Sep 14, 2017 at 12:00 PM, Jens Axboe <ax...@kernel.dk> 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.
Bjorn
