[+cc linux-pci, linux-kernel] On Thu, Jan 31, 2019 at 11:21 AM Lukas F. Hartmann <lukas@xxxxxxxxx> wrote: > > Hi Thinh, > > I'm writing you because you're the author in this commit: > https://github.com/torvalds/linux/commit/03e6742584af8866ba014874669d0440bed3a623 > > This quirk workaround breaks the PCIe on i.MX6QP, at least on my test > devices. The reason is because the Synposys PCIe IP in i.MX6QP has the > same device ID as the HAPS USB3 controller you are targeting in the > commit: 0xabcd. > > Definition: > > https://github.com/torvalds/linux/blob/master/include/linux/pci_ids.h#L2364 > > Here is a bit of lspci output on my i.MX6QP machine (without the problem): > > mntmn@reform:~/code/linux$ lspci -v > 00:00.0 PCI bridge: Synopsys, Inc. Device abcd (rev 01) (prog-if 00 > ^^^^ > [Normal decode]) > Flags: bus master, fast devsel, latency 0, IRQ 307 > Memory at 01000000 (32-bit, non-prefetchable) [size=1M] > Bus: primary=00, secondary=01, subordinate=ff, sec-latency=0 > ... > > The failure mode is that the PCIe controller shows up as a USB > controller and my ath9k wireless PCIe card cannot be assigned the > proper resources anymore (-ENOMEM even for very small BARs). > > Reverting this commit fixes the problem for me. I suggest to make the > check more specific to the platform/chipset you are targeting. So Synopsys apparently re-used Device ID 0xabcd? That's a pretty bad problem. It looks like we merged 03e6742584af ("PCI: Override Synopsys USB 3.x HAPS device class") for v5.0, and v5.0-final hasn't been released yet, so if we don't hear from Thinh with a resolution, we can still revert it. I set myself a reminder to revert this on Feb 11, but hopefully we'll have a better resolution before then. Bjorn
