Re: [PATCH 04/17] gpu: nova-core: allocate PCI MSI vector during probe

[Gary Guo]

On Thu Aug 13, 2026 at 10:31 PM BST, Danilo Krummrich wrote:
> On Sat Aug 8, 2026 at 5:11 AM CEST, John Hubbard wrote:
>> Allocate a single PCI MSI interrupt vector in the probe path.
>>
>> Try MSI/MSI-X first. If that fails (possible in broken VFIO setups),
>> fall back to INTx with a dev_warn so the issue is visible in dmesg.
>> The allocation is devres-managed and automatically freed on unbind.
>
> [...]
>
>> +pub(crate) fn alloc_vector(pdev: &pci::Device<Bound>) -> Result<pci::IrqVector<'_>> {
>> +    let msi_types = IrqTypes::default().with(IrqType::Msi).with(IrqType::MsiX);

BTW, we should convert this to use `impl_flags` so this becomes `IrqType::Msi | IrqType::MsiX`.

Best,
Gary

>
> I was about to ask if we really need to bother with MSI and shouln't just go for
> MSI-X only.
>
> But then saw that the commit message mentions broken VFIO setups; can you expand
> on this a bit? Which setups is the commit message referring to?