Bug#994971: OpenCL not working with latest Nvidia driver

[Andreas Beckmann]

On 26/09/2021 19.06, Klaus Ethgen wrote:
> Am So den 26. Sep 2021 um 17:58 schrieb Andreas Beckmann:
>> Thanks. You had modifications in nvidia-modprobe.conf, didn't try that
>> before.
> 
> Ehem, I don't think so... Never touched that file by hand.

You are probably right, dpkg just reported it as modified because it 
didn't know anything about the file at the point where it was going to 
remove it as obsolete conffile.

This was triggered by two bugs:
* debhelper (#994919) erroneously activated a new dpkg feature to remove 
obsolete conffiles. This works fine for the trivial cases, but not here 
where we replaced a conffile by an alternative to be able to select a 
driver version specific one (while allowing several drivers to be 
installed concurrntly).
* dpkg (#995387): the new remove-on-upgrade feature was removing (or 
rather renaming to *.dpkg-old because it considered it as modified) the 
target of a symlink, thus acting on a conffile owned by a different package

Luckily the conffile was still present as *.dpkg-old, so it is quite 
easy to detect this error and move the conffile back ;-)
Luckily this only affects the main driver series, I was afraid all the 
different variants would be affected as well, since the last uploads 
were all built with the buggy debhelper version. But they would only 
mishandle a nvidia-$VARIANT-modprobe.conf, which does not exist as an 
alternative ;-)


Andreas