Arch Linux

I upgraded [linux, linux-headers] to testing 5.5.1.arch1-1, to test the new kernel.
(These are the only two packages partial-upgraded, the rest is fully up-to-date with zero *testing package).

After successful upgrade & reboot, I noticed resume from suspend was broken:
*Suspend* does work, but once the laptop is suspended, pressing on POWER / Enter / whatever key (which under 5.4.x used
to resume the system) doesn't resume.
Instead, the machine doesn't do anything: system remains suspended, the glowing LED keeps glowing, and my only option is to force a hard shutdown with a long press on POWER, and start the system again.

Turning intel_iommu=off from my GRUB command line, I am able to successfully resume from suspend, like I used to be able to in 5.4.

This is the exact same problem that happened between kernel 4.12 and 4.13, for which I had filed kernel bug https://bugzilla.kernel.org/show_bug.cgi?id=197029 "intel_iommu=on under 4.13 breaks resume from suspend on my Thinkpad T560". The last promising news from this bug were from November 2017, when Lu Baolu from Intel said:

> This bug is still under investigation. We have narrowed it as a regression caused by a previous commit. The commit owner is now working on a fix

No news since then, and I didn't follow-up with Lu, because Arch stopped building with CONFIG_INTEL_IOMMU_DEFAULT_ON, meaning I stopped being affected by the bug.

1. I'm pinging Lu on the kernel bug.
2. Can Arch again unset this build flag?