Control: tags -1 + moreinfo Hi,
On Mon, Jan 19, 2026 at 09:08:11AM +0100, Jim Christian Dale Haukvik wrote: > Package: src:linux > Version: 6.12.63-1 > Severity: important > X-Debbugs-Cc: [email protected] > > Dear Maintainer, > > What led up to the situation? > I upgraded my system from Debian 13.2 to 13.3. This included a kernel update > from version 6.12.57 to 6.12.63. > > What exactly did you do (or not do) that was effective (or ineffective)? > I booted into the new kernel (6.12.63). I checked CPU usage using htop, which > was normal (under 5%), yet the fan remained at a high, constant speed. > I then rebooted and selected the previous kernel version (6.12.57) from the > GRUB advanced menu. > > What was the outcome of this action? > On kernel 6.12.57, the fan behaves normally (turning off or slowing down at > idle). On kernel 6.12.63, the fans are not turning off. > > What outcome did you expect instead? > I expected the fan management to remain functional as they were in the > previous > kernel version. This appears to be a regression in the 6.12.63 build. As, as far I understand you can reliably reproduce the problem, it would be great if you could bisect the problem. That would involve compiling and testing a few kernels: git clone --single-branch -b linux-6.12.y https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git cd linux-stable git checkout v6.12.57 cp /boot/config-$(uname -r) .config yes '' | make localmodconfig make savedefconfig mv defconfig arch/x86/configs/my_defconfig # test 6.12.57 to ensure this is "good" make my_defconfig make -j $(nproc) bindeb-pkg ... install the resulting .deb package and confirm the problem does not exists # test 6.12.63 to ensure this is "bad" git checkout v6.12.63 make my_defconfig make -j $(nproc) bindeb-pkg ... install the resulting .deb package and confirm the FAN problem exists With that confirmed, the bisection can start: git bisect start git bisect good v6.12.57 git bisect bad v6.12.63 In each bisection step git checks out a state between the oldest known-bad and the newest known-good commit. In each step test using: make my_defconfig make -j $(nproc) bindeb-pkg ... install, try to boot / verify if problem exists and if the problem is hit run: git bisect bad and if the problem doesn't trigger run: git bisect good . Please pay attention to always select the just built kernel for booting, it won't always be the default kernel picked up by grub. Iterate until git announces to have identified the first bad commit. Then provide the output of git bisect log In the course of the bisection you might have to uninstall previous kernels again to not exhaust the disk space in /boot. Also in the end uninstall all self-built kernels again. Additionally to the above, could you please as well check if the current version in unstable would expose as well the problem? Regards, Salvatore
