I'm not aware of any armhf hardware that has PCI and was supported by the 4.4 kernel. Calxeda gear maybe - but that was never officially released and I don't have access to it anyway.
I did regression test using the virt model in QEMU. System still boots, lspci smoke tests OK: ubuntu@ubuntu:~$ lspci 00:00.0 Host bridge: Red Hat, Inc. QEMU PCIe Host bridge Kernel messages during PCI probe look identical, except we now see ECAM messages (which makes sense, that support is new): 4.4.0+arm64acpipci.dmesg:[ 1.269192] PCI: CLS 0 bytes, default 64 4.4.0+arm64acpipci.dmesg:[ 6.708312] PCI host bridge /pcie@10000000 ranges: 4.4.0+arm64acpipci.dmesg:[ 6.747553] pci-host-generic 3f000000.pcie: PCI host bridge to bus 0000:00 4.4.0+arm64acpipci.dmesg:[ 6.792745] PCI: bus0: Fast back to back transfers disabled 4.4.0+arm64acpipci.dmesg:[ 7.012429] ehci-pci: EHCI PCI platform driver 4.4.0+arm64acpipci.dmesg:[ 7.037416] ohci-pci: OHCI PCI platform driver 4.4.0.dmesg:[ 1.309199] PCI: CLS 0 bytes, default 64 4.4.0.dmesg:[ 6.733705] PCI host bridge /pcie@10000000 ranges: 4.4.0.dmesg:[ 6.760085] pci-host-generic 3f000000.pcie: PCI host bridge to bus 0000:00 4.4.0.dmesg:[ 6.802961] PCI: bus0: Fast back to back transfers disabled 4.4.0.dmesg:[ 7.016247] ehci-pci: EHCI PCI platform driver 4.4.0.dmesg:[ 7.040325] ohci-pci: OHCI PCI platform driver -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1797092 Title: xenial guest on arm64 drops to busybux under openstack bionic-rocky Status in linux package in Ubuntu: Fix Released Status in linux source package in Xenial: Triaged Status in linux source package in Bionic: Fix Released Bug description: [Impact] on openstack rocky-bionic (with patch, see 1771662), xenial guests will fail to launch as they drop to the busybox prompt after booting. [Test Case] Deploy rocky-bionic OpenStack and try to launch a xenial guest. [Fix] Backport ACPI/PCIe support for arm64 from upstream. [ Regression Risk ] TLDR: Definitely warrants some regression testing on armhf/arm64, but regression risk seems low for other architectures. Here's a patch-by-patch risk analysis: > 0001-UBUNTU-Config-CONFIG_PCI_ECAM-y.patch Enables code that will be added in the next patch. > 0002-PCI-Provide-common-functions-for-ECAM-mapping.patch Only adds new code w/ no callers yet > 0003-PCI-generic-thunder-Use-generic-ECAM-API.patch As noted in the commit message: "The patch does not introduce any functional changes other than a very minor one: with the new code, on 64-bit platforms, we do just a single ioremap for the whole config space." > 0004-PCI-of-Move-PCI-I-O-space-management-to-PCI-core-cod.patch As noted, no functional change. > 0005-PCI-Move-ecam.h-to-linux-include-pci-ecam.h.patch As noted, no functional change. > 0006-PCI-Add-parent-device-field-to-ECAM-struct-pci_confi.patch This makes changes to the ecam code, but that was added in this series, so no regression risk there. The pci-thunder-pem changes will be regression tested on the hardware that uses that driver (Cavium ThunderX). > 0007-PCI-Add-pci_unmap_iospace-to-unmap-I-O-resources.patch Only adds new code, w/ no callers yet > 0008-PCI-ACPI-Support-I-O-resources-when-parsing-host-bri.patch Adds and calls a new function that is a no-op on !ARM (PCI_IOBASE is only defined on ARM). Also adds a call to pci_unmap_iospace(), which was added in a previous patch and is also a no-op on !ARM. > 0009-UBUNTU-Config-CONFIG_ACPI_MCFG-y.patch Enables code that will be added in the next patch. > 0010-PCI-ACPI-Add-generic-MCFG-table-handling.patch Adds parsing of a new ACPI table. A possible regression risk to platforms an MCFG table that were working fine w/ 4.4 and there's a latent bug in this parsing code. > 0011-PCI-Refactor-pci_bus_assign_domain_nr-for-CONFIG_PCI.patch As noted, no functional change intended. > 0012-PCI-Factor-DT-specific-pci_bus_find_domain_nr-code-o.patch Again, no functional change. > 0013-ARM64-PCI-Add-acpi_pci_bus_find_domain_nr.patch Only impacts ARM due to CONFIG_PCI_DOMAINS_GENERIC guard > 0014-ARM64-PCI-ACPI-support-for-legacy-IRQs-parsing-and-c.patch arm64-specific PCI initialization code - mitigate risk by regression testing on supported platforms (X-Gene, ThunderX). > 0015-ARM64-PCI-Support-ACPI-based-PCI-host-controller.patch Adds new code for arm64-ACPI support. We didn't previously support these devices, so regression risk is negligible. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1797092/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
