[OT] Compiling a module for the Fedora kernel

[Klaus-Peter Schrage]

Am 22.12.2014 um 17:52 schrieb Klaus-Peter Schrage:
> Am 22.12.2014 um 00:11 schrieb poma:
>> On 21.12.2014 19:45, Klaus-Peter Schrage wrote:
>>> Am 21.12.2014 um 18:34 schrieb Heinz Diehl:
>>>> On 21.12.2014, Klaus-Peter Schrage wrote:
>>>>
>>>>> I first tried the latest and greatest nouveau driver from
>>>>> freedesktop.org "as is", but the fan problem remains, so I
>>>>> still have to apply "my" patch to the nouveau source..
>>>>
>>>> I think you should file a bug against the nouveau driver on
>>>> bugs.freedesktop.org (xorg -> driver -> nouveau).
>>>
>>> Yes, I'll do so when I have figured out how to apply the patch to
>>> the nouveau driver from freedesktop.org. The patch is *againsts the
>>> kernel source*, like: --- a/drivers/gpu/drm/nouveau/core/... +++
>>> b/drivers/gpu/drm/nouveau/core/... but the structure of the driver
>>> from git is: nouveau/drm/core/... (sorry for being so clueless, but
>>> I never dealt with kernel modules ...)
>>>
>>
>> Check rhbz #1121331, recent comments.
>
> Thank you for your detailed instructions on bugzilla, they were easy to
> follow - but on reboot, the gpu fan began to roar like before, although
> no errors occurred during the process of building and installing the
> nouveau module:
>
> 1. The nouveau source from git got patched by your patchfile in exactly
> the same way as the kernel source tree got patched by "my" patchfile.
> The four respective files were identical.
>
> 2. The make process of the nouveau module finished without error, I
> copied nouveau.ko to
> /lib/modules/3.17.6-300.fc21.x86_64/updates/
>
> 3. After depmod, modinfo -n showed the appropriate location of the module:
> /lib/modules/3.17.6-300.fc21.x86_64/updates/nouveau.ko
>
> So I really can't figure out what happened, I repeated the process of
> rebuilding the complete kernel tree and got a quiet fan again ...
>
There is even more magic: I repeated the proposed build process of the 
patched nouveau driver after an update to the most recent kernel 
(3.17.7-300) - result again: a noisy fan.

Than (after booting into a different kernel) I removed 
kernel-3.17.7-300.fc21.x86_64 (and the corresponding kernel-core and 
kernel-modules), this, btw., left /lib/modules/3.17.7-300.fc21.x86_64/ 
untouched, including the module binary nouveau.ko.

Next step was an update to kernel-3.17.7-300.fc21.x86_64 again, and 
after booting into it, the fan was silent! modinfo -n nouveau says:
/lib/modules/3.17.7-300.fc21.x86_64/updates/nouveau.ko,
which is the binary that had survived the erasure of 3.17.7-300.

I really have no idea about the way modules get installed during a 
kernel update, but there seems to be something more than a "simple" 
depmod command that I gave after the initial modules build.