[REGRESSION] mainline/master: PCI link creation fails on Apalis iMX6

[Leonardo Costa]

Hello,

We are seeing a regression on Apalis iMX6 where connected PCI device
links fail to come up at initialization, as shown below. The issue is
not on the devices' physical connection, as they worked properly on v7.1
and are working on other stable kernel versions.

    [    0.154243] imx6q-pcie 1ffc000.pcie: host bridge /soc/pcie at 1ffc000 ranges:
    [    0.154400] imx6q-pcie 1ffc000.pcie:       IO 0x0001f80000..0x0001f8ffff -> 0x0000000000
    [    0.154439] imx6q-pcie 1ffc000.pcie:      MEM 0x0001000000..0x0001efffff -> 0x0001000000
    [    0.154553] imx6q-pcie 1ffc000.pcie: config reg[1] 0x01f00000 == cpu 0x01f00000
    [    0.356072] imx6q-pcie 1ffc000.pcie: iATU: unroll F, 4 ob, 4 ib, align 64K, limit 4G
    [    0.356181] imx6q-pcie 1ffc000.pcie: Link: Only Gen1 is enabled
    [    1.364757] imx6q-pcie 1ffc000.pcie: Link failed to come up. LTSSM: POLL_CONFIG
    [    1.365056] imx6q-pcie 1ffc000.pcie: probe with driver imx6q-pcie failed with error -110

Complete logs: https://paste.debian.net/hidden/f08cdf68

This may have been caused by commit [1], which was introduced to solve
an issue where the Apalis iMX6 module wasn't booting, and this second
regression went unnoticed since then.

Is it possible for all PCI changes to be reverted back to how they were
in v7.1 before the next release?

[1] 7678e81498e2 ("PCI: imx6: Fix i.MX6Q/DL boot hang caused by improper PHY power sequencing")
Link: https://lore.kernel.org/all/20260629143439.361560-1-leoreis.costa@gmail.com/