Re: PowerMac G5 fans run out of control with kernel 4.17.0-3-powerpc64 but not with 4.16.0-1-powerpc64
On Sep 2, 2018, at 11:08 PM, Mathieu Malaterre <malat@debian.org> wrote:
> On Sat, Aug 25, 2018 at 3:41 AM Rick Thomas <rbthomas@pobox.com> wrote:
>>
>>
>> I just loaded the latest Debian-ports powerpc64 installer on a PowerMac dual-core G5 that I had lying around.
>>
>> It installed kernel 4.16.0-1-powerpc64 from the CD. After the install finished, I did an update/upgrade and that installed kernel 4.17.0-3-powerpc64.
>>
>> A few minutes after rebooting with the new kernel the “wind tunnel” fans started up. I then rebooted with the old (4.16) kernel. The fans did not start up.
>>
>> Back in the old days of Linux kernel 3.x, the fix for wind tunnel fans was to load the “i2c_powermac" kernel module. Nowadays, that module is built-in so it isn’t necessary (or even possible) to manually load it. I checked the config files, and it is still built-in on both the 4.16 and the 4.17 kernels.
>>
>> Anybody know what changed and what can be done about it?
>
> Is this the same:
>
> https://bugzilla.kernel.org/show_bug.cgi?id=199471
>
> [Credit: Wolfram]
Thanks, Mathieu, for the pointer! And thanks, Wolfram, for the bug report!
Yeah, it fits. According to the comments, the regression was introduced in “4.16.03”. The kernel that, for me, didn’t need to have windfarm modules loaded manually was “4.16.0-1”. The kernel in which I noticed the bug (need to load windfarm manually) was “4.17.0-3”. So I’m guessing that’s the culprit.
The bug is “status: NEEDINFO”, so I assume it’s not fixed yet. In the meantime, manually loading the windfarm modules is a tested workaround.
Enjoy!
Rick
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