[Bug 220906] Regression: 4K display output fails on ThinkPad Thunderbolt 4 Dock with AMD GPU (Worked in 6.17.1, broken in 6.17.11)

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=220906

--- Comment #7 from Andrei (danandrei@gmail.com) ---
I initially thought this was just an AMD driver bug, but after digging through
the logs across a few more versions, I think I’ve found a better lead.

In 6.17.6, where the regression started for the first time, I'm seeing these
bridge resource failures pop up for the first time:

pci 0000:02:00.0: bridge window [io  size 0x1000]: can't assign; no space
pci 0000:02:00.0: bridge window [io  size 0x1000]: failed to assign

Bridge 02:00.0 is the gateway for the USB4/Thunderbolt 4 controller on this
machine. In version 6.17.5, the kernel assigns it just fine and my 4K output
works perfectly. Starting with 6.17.6, that assignment fails, which lines up
exactly with when the display stops working.

Interestingly, the ath12k driver also starts throwing an "invalid ACPI DSM TAS
config size" error in this same version. It feels like 6.17.6 changed something
fundamental about how ACPI or PCI resource arbitration is handled, and now it's
just choking out the I/O space that the Thunderbolt subsystem needs to
function.

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