On Wed, May 25, 2022 at 04:57:39PM -0500, Bjorn Helgaas wrote: > On Tue, May 24, 2022 at 12:54:48PM -0400, Jim Quinlan wrote: > > On Mon, May 23, 2022 at 6:10 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > On Sat, May 21, 2022 at 02:51:42PM -0400, Jim Quinlan wrote: > > > > On Sat, May 21, > > > > 2CONFIG_INITRAMFS_SOURCE="/work3/jq921458/cpio/54-arm64-rootfs.cpio022 > > > > at 12:43 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > > > On Wed, May 18, 2022 at 03:42:11PM -0400, Jim Quinlan wrote: > > > > > > commit 93e41f3fca3d ("PCI: brcmstb: Add control of subdevice > > > > > > voltage regulators") > > > > > > > > > > > > introduced a regression on the PCIe RPi4 Compute Module. If the > > > > > > PCIe endpoint node described in [2] was missing, no linkup would > > > > > > be attempted, and subsequent accesses would cause a panic > > > > > > because this particular PCIe HW causes a CPU abort on illegal > > > > > > accesses (instead of returning 0xffffffff). > > > > > > > > > > > > We fix this by allowing the DT endpoint subnode to be missing. > > > > > > This is important for platforms like the CM4 which have a > > > > > > standard PCIe socket and the endpoint device is unknown. > > > > But above you say it's the *endpoint* node that doesn't exist. The > > > existing code looks like it's checking for the *bridge* node > > > (bus->dev->of_node). We haven't even enumerated the devices on the > > > child bus, so we don't know about them at this point. > > > > You are absolutely correct and I must change the commit message > > to say the "root port DT node". I'm sorry; this mistake likely did not > > help you understand the fix. :-( > > Great, that will help me out! I think including the relevant DT > snippet would also make it more concrete and might conceivably be > helpful to somebody working around it on a kernel without the fix. Where are we at with this? Linus just merged my pull request, and I'd really like to get this resolved before -rc1 (expected June 5 or so), which means I'd like to ask him to pull the fix early next week. The alternative is to ask him to pull these reverts, which have actually been in -next since May 11: 4246970a3bcb ("Revert "PCI: brcmstb: Split brcm_pcie_setup() into two funcs"") f35b19f02e01 ("Revert "PCI: brcmstb: Add mechanism to turn on subdev regulators"") ae65b283d7a4 ("Revert "PCI: brcmstb: Add control of subdevice voltage regulators"") d938b26e9b14 ("Revert "PCI: brcmstb: Do not turn off WOL regulators on suspend"") Bjorn