pci_alloc_irq_vectors fails ENOSPC for XPS 13 9310

[Thomas Gleixner]

On Wed, Nov 04 2020 at 14:04, Thomas Krause wrote:
> config) but CONFIG_INTEL_IOMMU_DEFAULT_ON needed to be set manually. I 
> hope this helps, if there is more I can do to debug it on my side I'm 
> happy to do so.

> [    0.050130] DMAR: [Firmware Bug]: Your BIOS is broken; DMAR reported at address 0!
>                BIOS vendor: Dell Inc.; Ver: 1.1.1; Product Version:

> [    0.103693] DMAR: Host address width 39
> [    0.103693] DMAR: DRHD base: 0x000000fed90000 flags: 0x0
> [    0.103697] DMAR: dmar0: reg_base_addr fed90000 ver 4:0 cap 1c0000c40660462 ecap 69e2ff0505e
> [    0.103698] DMAR: DRHD base: 0x000000fed84000 flags: 0x0
> [    0.103701] DMAR: dmar1: reg_base_addr fed84000 ver 1:0 cap d2008c40660462 ecap f050da
> [    0.103702] DMAR: DRHD base: 0x000000fed86000 flags: 0x0
> [    0.103706] DMAR: dmar2: reg_base_addr fed86000 ver 1:0 cap d2008c40660462 ecap f050da
> [    0.103707] DMAR: DRHD base: 0x00000000000000 flags: 0x1
> [    0.103707] DMAR: Parse DMAR table failure.

which disables interrupt remapping and therefore the driver gets only
one MSI which makes it unhappy.

Not that I'm surprised, it's Dell.... Can you check whether they have a
BIOS update for that box?

Thanks,

        tglx