Created attachment 300347 [details]
dmesg output

System:
Dell XPS 9550 (2015)
Distro:
Arch Linux

On 5.15 and 5.16 kernels, if my laptop is plugged in prior to booting or is plugged in at any time after booting I see high CPU usage (80-100% of a core) by IRQ 16, with a constant 15k+ IRQ events per second, whether the system is in use or not. Unplugging the laptop does not make the events stop. If I boot the system without it being plugged in the issue does not occur until I plug it in. Downgrading to 5.14 fixes the issue completely, with only 3 total IRQ 16 interrupts after the system as been running for > 20 minutes. I do not see IRQ16 interrupts increase by using the touch pad, keyboard, or touch screen. I believe I was able to bisect the introduction of the issue to commit 357cf0cdddceea974a7d32668a0df0d9f77055cb, but this was the first time I've done kernel bisects before, so I may be incorrect. I tested with 5.17 RC1 and the issue was still present.

I've attached dmesg output and the contents of lspci -vvvv, as well as included IRQ 16 info from /proc/interrupts. Please let me know if I can provide anything else.

/proc/interrupts:
  16:          0          0    7513443          0          0          0          0          0  IR-IO-APIC   16-fasteoi   idma64.0, i801_smbus, i2c_designware.0