Confusion on alternatives for /usr/lib/xorg/modules/linux/libglx.so

[Andreas Beckmann]

On 2018-07-15 09:00, Hualet Wang wrote:
> Hi, Debian NVIDIA Maintainers 
> 
> Recently I’m trying port nvidia-prime to our distribution,

We might be interested in the result of that project.
https://bugs.debian.org/875959

> deepin which is a Debian Sid derivative, during the process I found that users with nvidia-dirver installed, some of them got /usr/lib/xorg/modules/linux/libglx.so and some of them didn’t, and among the users who got /usr/lib/xorg/modules/linux/libglx.so, some of their X load that file when LoadModule glx happens, and the others just load /usr/lib/xorg/modules/extensions/libglx.so.

This should be fixed wth 390.67-2.

> I checked postinst script of glx-alternative-nvidia, and see it "handles alternatives for /usr/lib/xorg/modules/linux/libglx.so”.
> 
> So I’m totally confused:
> [1] why there’s an alternatives for /usr/lib/xorg/modules/linux/libglx.so ? 

NVIDIA provides their own libglx.so xorg module. You need that instead
of the standard Xorg one if you use the nvidia driver in Xorg (but not
in e.g. bumblebee setups)

Historically we placed it in linux/ since that path was prepended to the
search path (up to Xserver 1.19) and the module was found there (if the
slave alternative put it there). With Xserver 1.20+ we need to manually
set the search path in the Xorg config to achieve this (done since
390.67-1).

> [2] how the nvidia-driver suppose to change the behavior that which libglx.so is loaded ?

It will not work (efficently) if the wrong one is loaded.


Feel free to ask more questions.


Andreas