Per PCIe r3.1, sec 2.2.6.2 and 7.8.4, a Requester may not use 8-bit Tags
unless its Extended Tag Field Enable is set, but all Receivers/Completers
must handle 8-bit Tags correctly regardless of their Extended Tag Field
Enable.

Some devices do not handle 8-bit Tags as Completers, so add a quirk for
them.  If we find such a device, we disable Extended Tags for the entire
hierarchy to make peer-to-peer DMA possible.

The Broadcom HT1100/HT2000/HT2100 seems to have issues with handling 8-bit
tags.  Mark it as broken.

This fixes Xorg hangs and unresponsive keyboards with errors like this:

  radeon 0000:06:00.0: GPU lockup (current fence id 0x000000000000000e last fence id 0x0000000000000
  [drm:r600_ring_test [radeon]] *ERROR* radeon: ring 0 test failed (scratch(0x8504)=0xCAFEDEAD)
  [drm:r600_resume [radeon]] *ERROR* r600 startup failed on resume

Fixes: 60db3a4d ("PCI: Enable PCIe Extended Tags if supported")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196197Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
CC: stable@vger.kernel.org	# v4.11: 62ce94a7 PCI: Mark Broadcom HT2100 Root Port Extended Tags as broken
CC: stable@vger.kernel.org	# v4.11