Comment by IshKebab

It's ACPI - most laptops ship with half-broken ACPI tables, and provide support for tunables through windows drivers. It's convenient for laptop manufacturers, because Microsoft makes it very easy to update drivers via windows update, and small issues with sleep, performance, etc. can be mostly patched through a driver update.

Linux OTOH can only use the information it has from ACPI to accomplish things like CPU power states, etc. So you end up with issues like "the fans stop working after my laptop wakes from sleep" because of a broken ACPI implementation.

There are a couple of laptops with excellent battery life under linux though, and if you can find a lunar lake laptop with iGPU and IPS screen, you can idle around 3-4W and easily get 12+ hours of battery.

> Does anyone know why Linux laptop battery life is so bad?

It's extremely dependent on the hardware and driver quality. On ARM and contemporary x86 that's even more true, because (among other things) laptops suspend individual devices ("suspend-to-idle" or "S0ix" or "Modern Standby"), and any one device failing to suspend properly has a disproportionate impact.

That said, to a first approximation, this is a case where different people have wildly different experiences, and people who buy high-end well-supported hardware experience a completely different world than people who install Linux on whatever random hardware they have. For instance, Linux on a ThinkPad has excellent battery life, sometimes exceeding Windows.

Newer laptops come with extra power peripherals and sensors. Some of them are in ACPI tables, some are not. Most of them are proprietary ASICs (or custom chips, nuvoton produces quite a bit of those). Linux kernel or the userspace has poor support for those. Kernel PCIe drivers require some tuning. USB stack is kind of shaky and power management features are often turned off since they get unstable as hell.

If you have a dGPU, Linux implementation of the power management or offloading actually consumes more power than Windows due to bad architectural design. Here is a talk from XDC2025 that plans to fix some of the issues: https://indico.freedesktop.org/event/10/contributions/425/

Desktop usage is a third class citizen under Linux (servers first, embedded a distant second). Phones have good battery life since SoC and ODM engineers spend months to tune them and they have first party proprietary drivers. None of the laptop ODMs do such work to support Linux. Even their Windows tooling is arcane.

Unless the users get drivers all the minute PMICs and sensors, you'll never get the battery life you can get from a clean Windows install with all the drivers. MS and especially OEMs shoot themselves in the foot by filling the base OS with so much bloat that Linux actually ends up looking better compared to stock OEM installs.

In addition to the other comments, its worth noting macOS started adding developer documentation around energy efficiency, quality of service prioritization, etc. (along with support within its OS) around 2015-2016 when the first fanless usb-c macbook came out: https://developer.apple.com/library/archive/documentation/Pe...

Think I'm arguing its both things where the OS itself can optimize things for battery life along with instilling awareness and API support for it so developers can consider it too.

My Dell XPS had pretty good battery life on linux. Probably better than on windows. But Dell sells the XPS wiht linux preinstalled. So I assume it has a lot to do with the drivers. Many notebooks have custom chips inside or some weird bios that works together with a windows program. I'd say laptops are more diverse than desktop PCs with of the shelve hardware.

A big part of it is chipmakers deprecating S3 sleep in favour of Modern Standby.

Install powertop, the "tunables" tab has a list of system power saving settings you can toggle through the UI. I've seen them make a pretty big difference, but YMMV of course.

I ran into this problem on a Slimbook some years ago now. I found that my battery drained way too fast in standby, and I remember determining that this was some (relatively common) problem with sleep states, that some linux machines couldn't really enter/stay in a deeper sleep state, so my Slimbook's standby wasn't much of a standby at all.

But that's just one problem, I bet.

A lot of people say that lightweight desktops/distros help. Probably GNOME/KDE unnecessarily use your SSD, network, GPU and other resources even when you are idle, compared to using a minimal WM and only starting the daemons you actually need.

I personally never tested it, and I can't find definite benchmarks that confirm and measure the waste.

I've found that it can be made considerably better than Windows on the same hardware, but it requires substantial effort.

While each of the comments here describe individual failings, on a well supported laptop it is possible to get better power efficiency than windows if your willing to spend the time manually tuning linux, the powertop/etc suggestions are fine, but fundamentally the reason some of the 'lighter' DE's save so much power is that there is a lot of 'slop' in the default KDE/GNOME and application set. You have random things waking up to regularly and polling stuff which pulls the cores out of deep sleep states. And then there are all the kernel issues with being unable to identify and prioritize/schedule for a desktop. Ex: the only thing that should be given free reign is an active forground application, grouping and suppressing background applications, running them on little cores at slow rates if they have work to do/etc. All that is a huge part of why macos does so well vs linux on the same hardware.

The comment about ACPI being the problem is slightly off base, since its a huge part of the solution to good power management on modern hardware. There isn't another specification that allows the kind of background fine grained power tuning of random busses/devices/etc by tiny management cores who's entire purpose is monitoring activity and making adjustments required of modern machines. If one goes the DT route as QC has done here, each machine needs a huge pile of custom mailbox interface drivers upstreamed into the kernel customized for every device and hardware update/change. They get away with this in the android space because each device is literally a customized OS and they don't have the upstream turnaround problem because they don't upstream any of it, but that won't scale for general purpose compute as the parent article talks about.