Aw: Re: [PATCH] pci: mediatek: fix warning in msi.h
Marc Zyngier
maz at kernel.org
Tue Nov 3 05:29:17 EST 2020
On 2020-11-03 10:16, Thomas Gleixner wrote:
> On Tue, Nov 03 2020 at 09:54, Marc Zyngier wrote:
>> On 2020-11-02 22:18, Thomas Gleixner wrote:
>>> On Mon, Nov 02 2020 at 17:16, Thomas Gleixner wrote:
>>>> On Mon, Nov 02 2020 at 11:30, Marc Zyngier wrote:
>>>>> --- a/drivers/pci/probe.c
>>>>> +++ b/drivers/pci/probe.c
>>>>> @@ -871,6 +871,8 @@ static void pci_set_bus_msi_domain(struct
>>>>> pci_bus
>>>>> *bus)
>>>>> d = pci_host_bridge_msi_domain(b);
>>>>>
>>>>> dev_set_msi_domain(&bus->dev, d);
>>>>> + if (!d)
>>>>> + bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
>>>>
>>>> Hrm, that might break legacy setups (no irqdomain support). I'd
>>>> rather
>>>> prefer to explicitly tell the pci core at host registration time.
>>>
>>> s/might break/ breaks / Just validated :)
>>
>> For my own edification, can you point me to the failing case?
>
> Any architecture which selects PCI_MSI_ARCH_FALLBACKS and does not have
> irqdomain support runs into:
>
> if (!d)
> bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
>
> which in turn makes pci_msi_supported() return 0 and consequently makes
> pci_enable_msi[x]() fail.
I pointer that out in [1], together with a potential fix. Not sure if
anything else breaks though.
Thanks,
M.
[1]
https://lore.kernel.org/r/336d6588567949029c52ecfbb87660c1@kernel.org/
--
Jazz is not dead. It just smells funny...
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