[EdLUG] Linux hibernate

[timday]

On Sat, 2022-09-17 at 20:12 +0100, Colin Shorts wrote:
Trial and error might be called for. Perhaps a newer kernel might help too?

Sometimes upgrades make things worse!

I have a machine here that spends most of its time suspended until hit by a wake-on-lan (its a "backup server" that other machines rsync to) which had been working happily until I upgraded it from Debian 10 to 11... at which point it became incredibly unreliable about it.

The issue seemed to be something in the nouveau driver.  (Typical bug report https://lists.debian.org/debian-kernel/2021/08/msg00281.html )
Using an "official" nvidia driver wasn't an option as the machine's GPU is now behind even what nvidia's "legacy" drivers support, but I never use the machine graphically... it's just a headless server, so I just did whatever systemd thing never bothers to fire up the graphics and its suspend/WoL has been back working just fine again since.

Anyway, just an example of the sort of mayhem that can result (even in Debian stable).  No idea whether Ubuntu managed to sidestep the same issue, but googling "Ubuntu Nouveau suspend" finds lots of reports of issues logged 2021-2022 which sound similar to what I was seeing, so if you've Nvidia graphics HW and use the Nouveau driver be aware you might run into this.

There used to be a Linux joke that "suspend and resume" was actually "suspend and...???".  It's still pretty true.
Tim

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