Reverting rmmod->modprobe change in bumblebee/3.2.1-8 (was: Re: Bumblebee functionality broken by the last update made by Vincent Cheng on 26-July-2015 - please react as fast as possible)

[Luca Boccassi]

On Fri, 2015-08-07 at 11:39 +0200, Peter Wu wrote:
> Hi Luca,
> 
> I just did some tests with a Ubuntu 14.04 VM:
> 
>     sudo rm /lib/modules/`uname -r`/kernel/drivers/char/lp.ko
>     sudo depmod
> 
> This simulates a mismatch between the kernel module and its file name.
> For testing, I use the following mapping between module names and files:
>     lsmod name  | filename  | simulates
>     lp          | crc7.ko   | nvidia/nvidia-current.ko
>     ppdev       | ppdev.ko  | nvidia-uvm/nvidia-uvm.ko
> 
> Then, I tried the following modprobe conffiles and commands:
> 
>  - alias nvidia nvidia-current
>    modprobe -vr nvidia
>    No effect!
>  - alias nvidia nvidia-current
>    modprobe -v nvidia
>    Loads nividia-current.ko
>  - remove nvidia nvidia-uvm nvidia-current
>    modprobe -vr nvidia
>    Works, but the exit code is always 1 if one of the modules failed to
>    unload.
> 
> Why does Debian not have this issue while Ubuntu does? Debian uses the
> last option[0], Ubuntu apparently does not. I suggest to keep the Debian
> packaging as is because it fixes a real issue (nvidia-uvm should be
> unloaded first) and instead modify the Ubuntu packages.
> 
> Since Ubuntu has so many nvidia versions, should it be put in the
> bumblebee package (since that is the only user for now) or should it be
> addressed in each nvidia package? (Tested it, only the first 'remove'
> command will be used in presence of duplicate lines.)
> 
> Kind regards,
> Peter
> 
>  [0]: https://sources.debian.net/src/nvidia-graphics-drivers/340.76-3/debian/nvidia-modprobe.conf.in/

Hi Peter,

Thanks for doing this test.

As you correctly pointed out, the reason Debian does not have the
problem is because it uses the last method in the modprobe config file.
Although it exits 1 (on the list to find a solution for that), both
modules are correctly removed if present.

I do not know yet if there is the same problem with nvidia-uvm on
Ubuntu, nor what is the proper solution for Ubuntu, I plan to
investigate later tonight or tomorrow.

Kind regards,
Luca Boccassi
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