[PATCH 0/2] Add PCI quirk for Tenstorrent Blackhole to work on systems without enough host bridge aperture space

[Anirudh Srinivasan]

This series adds a PCI quirk to let Tenstorrent Blackhole cards to
function on systems that have smaller PCI host bridge windows by
dropping the 32GiB BAR4 that is unused by software. First patch adds
the Tenstorrent vendor ID to pci_ids.h and second patch adds the quirk.
The quirk checks if the host doesn't have any windows that are atleast
32GiB, and drops BAR4 if that's the case.

I realize that this patch doesn't account for every single case where
BAR 4 prevents Blackhole from being usable. Many of the reported cases
are ones where one Blackhole would work, but multiple won't. Examples
are cases on some x86 mining systems with limited BAR space/KVM guests
with limited PA bits that don't have BAR space for 8 blackholes. To do
this correctly, one would have to try allocating every other device
first, try Blackhole last, and drop BAR 4 if that fails. This doesn't
seem to be possible to my understanding.

I'm still submitting this patch cause it helps in many cases where even
a single Blackhole wouldn't work.

Signed-off-by: Anirudh Srinivasan <asrinivasan@xxxxxxxxxxxxxxxxxxx>
---
Anirudh Srinivasan (2):
      PCI: Add Tenstorrent vendor ID to linux/pci_ids.h
      PCI: quirks: Drop unassignable 32 GiB BAR 4 on Tenstorrent Blackhole

 drivers/pci/quirks.c    | 32 ++++++++++++++++++++++++++++++++
 include/linux/pci_ids.h |  2 ++
 2 files changed, 34 insertions(+)
---
base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
change-id: 20260824-blackhole_quirk-a31209323a62

Best regards,
--  
Anirudh Srinivasan <asrinivasan@xxxxxxxxxxxxxxxxxxx>