XPost: linux.debian.bugs.dist   
   From: carnil@debian.org   
      
   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: jchaukvik@gmail.com   
   >   
   > 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   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)