Re: [GIT PULL v2] PCI changes for v6.17

[Ammar Faizi <ammarfaizi2@gnuweeb.org>]

+ Adding tglx as he's involved in reviewing that commit.

Context: https://lore.kernel.org/linux-pci/aJXYhfc%2F6DfcqfqF@linux.gnuweeb.org/

On Fri, Aug 08, 2025 at 08:07:03PM +0200, Nam Cao wrote:
> There is no point in bisecting before that commit, because the WARN_ON()
> is added by that commit, so you wouldn't see anything before that.

I didn't notice that. Good you pointed that out earlier.

> The WARN_ONCE() tells us that some devices down the PCI tree are
> allocating MSI, but VMD supports MSI-X only.
> 
> From the backtrace:
>    msi_create_device_irq_domain+0x1eb/0x290
>    __pci_enable_msi_range+0x106/0x300
>    pci_alloc_irq_vectors_affinity+0xc5/0x110
>    pcie_portdrv_probe+0x24e/0x610
> 
> It seems MSI-X are allocated first, but fail for some reason. Then
> fallback to MSI, which triggers the WARN_ON().
> 
> So we need to figure out why MSI-X allocation fail.
> 
> I may need to ask you to insert a bunch of printk() to help me pinpoint
> the problem. But let me stare at it first..

I can do that. Send me a git diff. I'll test it and back with the dmesg
output.

-- 
Ammar Faizi