Linux kernel 6.12 is out now with real-time capabilities, more gaming handheld support

Here it is, another big Linux kernel release is out now. Linux kernel 6.12 is an exciting one too with a big feature finally landing.

From the release announcement, Linus Torvalds said:

No strange surprises this last week, so we're sticking to the regular release schedule, and that obviously means that the merge window opens tomorrow. I already have two dozen+ pull requests in my mailbox, kudos to all the early birds.

But before the merge window opens, please give this a quick test to make sure we didn't mess anything up. The shortlog below gives you the summary for the last week, and nothing really jumps out at me. A number of last-minute reverts, and some random fairly small fixes fairly spread out in the tree.

The real big one for this release is the enabling of PREEMPT_RT, implementing real-time computing capabilities. This was merged by Linus Torvalds on September 20th from Thomas Gleixner that noted:

Enable PREEMPT_RT on supported architectures:

After twenty years of development we finally reached the point to enable PREEMPT_RT support in the mainline kernel.

All prerequisites are merged, so enable it on the supported architectures ARM64, RISCV and X86(32/64-bit)

There's a good interview on Linux.com to give a bit of background on it, here's an excerpt where Gleixner explained what it actually really means:

TG: Real-Time in the context of operating systems means that the operating system provides mechanisms to guarantee that the associated real-time task processes an event within a specified period of time. Real-Time is often confused with “really fast.” The late Prof. Doug Niehaus explained it this way: “Real-Time is not as fast as possible; it is as fast as specified.”

The specified time constraint is application-dependent. A control loop for a water treatment plant can have comparatively large time constraints measured in seconds or even minutes, while a robotics control loop has time constraints in the range of microseconds. But for both scenarios missing the deadline at which the computation has to be finished can result in malfunction. For some application scenarios, missing the deadline can have fatal consequences.

In the strict sense of Real-Time, the guarantee which is provided by the operating system must be verifiable, e.g., by mathematical proof of the worst-case execution time. In some application areas, especially those related to functional safety (aerospace, medical, automation, automotive, just to name a few), this is a mandatory requirement. But for other scenarios or scenarios where there is a separate mechanism for providing the safety requirements, the proof of correctness can be more relaxed. But even in the more relaxed case, the malfunction of a real-time system can cause substantial damage, which obviously wants to be avoided.

Some other fun stuff added in this kernel release include:

• Expanded oxp-sensors support for OrangePi NEO-01, OneXPlayer 2 series, OneXFly, and X1 series. Plus AYANEO models 2S, AIR 1S, Flip series, GEEK 1S, and KUN.
• Fixed up ROG ALLY X audio support.
• Added support for the GameForce Ace handheld (Rockchip RK3588s SoC).
• Improved support for the Anbernic RG28XX handheld (H700 ARM Cortex-A53).
• Improved Raspberry Pi 5 support.
• Intel Battlemage and Lunar Lake support enabled by default.
• Intel graphics fan speed reporting.
• More work towards supporting Intel Panther Lake.
• Support for showing a QR code for Linux kernel panics.
• Lots of improved support for various laptops.
• sched_ext, "a scheduler class whose behavior can be defined by a set of BPF programs" is now in.

I'm just searching through and cherry-picking random bits here as usual. It's a ridiculously long read as always with thousands of changes across all areas. See more in the full changelog.

Is there a particular change you're excited to see that made it into Linux kernel 6.12? Let me know in the comments.