Kernel 6.9 halved my battery life (AMD) and broke Energy Saver

On 6.8 I would get about 4.5 hrs, especially on Energy Saver mode. Ever since 6.9, I noticed Energy Saver shifts the display to a strange color profile where everything is really washed out and kind of over-exposed looking, which seems to be intended to compensate for a lower display brightness. That’s no big deal, though it would be nice to be able to configure or disable it.

More importantly, it basically cut my battery life in half. In fact, after unplugging and switching to Energy Saver, I can watch the power consumption steadily increase to nearly 30W while basically sitting at idle. It also runs warmer. Sometimes switching power modes will get the consumption to drop momentarily, but then it steadily climbs back up even while doing practically nothing.

I suspect this has to do with the AMD P-State additions made to the 6.9 kernel, so I’m curious if there’s a way to get P-State management under control with 6.9?

But in the mean time, I used dnf versionlock to lock my 6.8 kernel install, and set it to my default in grub. Colors under Energy Saver are back to normal, and so is battery life.

So this weird power management issue seems to be common for AMD devices. You can try the workaround mentioned above. For me, it draws about 12W in battery mode and around 30W when connected to AC. It also fixes the weird display issue.

Thanks for posting this! Did you by chance have the same battery drain issue before switching to tlp?

I didn’t check power consumption at the time. It may have drained more power, but I just didn’t notice.

Did a little testing this morning, with and without tlp, and under 6.8 and 6.9. Switching to tlp definitely takes care of the weird washed out colors behavior on 6.9, and while it does seem to improve battery life slightly, it’s still not as good as 6.8 with the standard power management service, for me at least. I suspect the battery life is still bad on 6.9 because of the P-State behavior keeping some cores at a higher minimum voltage.

For now I’ll stick to 6.8, hopefully when Fedora 41 brings the new “tuned” power manager it’ll have a better handle on AMD P-State.

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Tuned is already available to install on F40 (it was there for f39 as well).

You may be able to install it and switch over already. f41 still is about 4 months away

Good to know, I may give it a shot! Do you happen to know if it can integrate into the DE like the default system does? By which I mean how we can easily swap between Energy Saver/Balanced/Performance from the tray icon. Losing that was a bit of a turnoff from when I tried tlp.

I’m a bit new to Fedora/Linux so apologies if I’m not using the correct terminology here.

Just wanted to follow up on this and mention that there have been a few more version updates to the Kernel, and as of 6.9.6-200, I seem to be getting more or less the same battery life/power consumption as I did on 6.8. Might just be placebo, or might be the result of the updated AMD drivers, but 6.9 does feel a bit snappier, so I’ll stick with it for now.