Bug 2533325

After performing a system update 45 minutes ago, the screen brightness control (both the keyboard shortcut and the UI when clicking the settings menu in the top bar) is broken - my eyeballs are currently being fried. Furthermore, brightness adjustment is painfully slow, and again, does nothing. Toggling night light brings my system to a crawl for 3 seconds or so before resuming normal operation, but does work.

Also, hibernation works - I can force my machine in and out of hibernation, but my CPU fan kicks on at regular intervals in a pattern. Every five seconds or so, this pattern repeats. It has two very short (~0.1s) pulses, then a slightly longer one (~0.5s) after a brief interval of silence. It is very faint when they do kick on. 

I'm seeing a ton of amdgpu errors in my logs (138 in a span of two minutes), only occurring exactly after doing the update. The two errors are generated anew each time I try to adjust the brightness. The errors in question are the same two:
"amdgpu 0000:05:00.0: [drm] *ERROR* dc_dmub_srv_log_diagnostic_data: DMCUB error - collecting diagnostic data" and "amdgpu 0000:05:00.0: [drm] *ERROR* Error queueing DMUB command: status=2", generated in that order.

Rebooting, manually shutting the machine off and on again and suspending do nothing.

(Relevant) System information:
* Lenovo ThinkPad E14 G6
* Unmodified (by me) AMD Rembrandt Radeon 680M on the amdgpu driver which came with Fedora.
* Kernel version 7.2.5-200.fc44.x86_64

Reproducible: Always

Steps to Reproduce:
1. Perform a system update to kernel version 7.2.5-200.fc44.x86_64 on my hardware.
2. Have eyeballs fried upon boot.
3. Cry.
Actual Results:
* The display brightness was stuck on max without remedy.
* Toggling the night light slows my system to a crawl for three or so seconds.
* CPU fans kick on in the pattern described in the description.

Expected Results:
* The display brightness should be modifiable as before the update.
* Toggling night light should work as before the update - responding immediately, not slowing the system noticeably.
* CPU fans should remain off during hibernation as they were before the update.