Dear Maintainers,

On my ThinkPad L14 Gen 2 AMD (20X6S0K400), resuming from suspend-to-idle
consistently leaves the built-in display black for approximately 10 seconds
before the lock screen appears. Locking without suspending does not cause
this delay.

System:

- Debian 13, kernel package version 6.12.113-1
- Running kernel: 6.12.113+deb13-amd64
- BIOS: R1KET46W (1.31), dated 2024-04-02
- NVMe: WDC PC SN730 SDBQNTY-512G-1001, firmware 11170101
- Suspend mode: s2idle

Without additional kernel parameters, kernel timestamps show approximately
10 seconds between “ACPI: EC: interrupt unblocked” and the start of AMD
graphics resume.

Booting the same kernel with iommu=pt eliminates the visible delay.

I expected resume to restore the display promptly without requiring IOMMU
passthrough.

A potentially relevant observation is that the AMD PMC firmware workaround table
includes L14 Gen 2 AMD machine type 20X5, but not my 20X6. This omission is
also present in current upstream source. Could maintainers assess whether the
existing workaround should cover 20X6? I have not tested a patched or
upstream-built kernel.

A similar report for another omitted sibling model, X13 Gen 2 AMD 20XJ,
is Ubuntu bug #2168884:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2168884