== Summary ==
On my computer with an ancient Nvidia chipset (Geforce 7025/nForce 630a), running `sysctl suspend` (or suspending from the Gnome menu) causes the system to start suspending, but it freezes halfway, leaving fans and hard drives spinning. There’s no way to resume from this frozen state apart from forcing a reboot (with a hardware reset button/poweroff).

== Steps to reproduce ==
* boot with modeset enabled
* run `sysctl suspend`

== What I expect to happen ==
For the system to suspend, shutting down all fans and hard drives.

== What happens ==
The system begins to suspend, but freezes halfway, leaving the display on and fans and hard drives spinning, but the keyboard unresponsive.

== Workaround ==
Disable kernel modesetting by adding ”nomodeset” to the kernel commandline.

== Affected kernels ==
Prior to upgrades the system was running HWE kernel 5.15.0, so I tried the 5.15 series, and found that I could now suspend and wake the machine again just as before. I worked my way up the versions:

* 5.15.50: unaffected
* 5.15.165: unaffected
* 5.19.17: unaffected
* 6.4.0: unaffected
* 6.6.0: unaffected
* 6.6.48: unaffected
* 6.7.0: first to fail

I also tried the current newest mainline kernel 6.10.7, and the issue is still present there.

== Background ==
I have an old desktop machine now functioning as a NAS, and yesterday I upgraded it from Ubuntu 20.04 first to 22.04, and then all the way up to 24.04. The upgrade went smoothly, and this is the only issue I’ve come across since.

In the BIOS settings of the affected machine there are three ”suspend mode” alternatives to choose from: ”S1 (POS) only”, ”S3 only” and ”Auto”. I’ve always had it on ”Auto”, but with this issue I also tested both ”S1 only” and ”S3 only”, with no effect.

The issue is also present when booting from the installation media (USB) into a live environment.

I’ve previously upgraded my laptop to 24.04, and there suspending still works as it did before the ugprade, so this is probably hardware-specific; the laptop is a modern one with all-Intel hardware.

Googling around, I could smelled hints of this being once again related to the troublesome Nvidia chipset, so I tried nomodeset with the stock 6.8.0 kernel (6.8.0-41 currently) and voilà! Suspend and wake were working again.

Well, except for the display, which stayed black. But I couldn’t say if this was the way it was before, because the NAS is normally running headless.