Bug#1077266: glx-diversions: does not divert libGLX.so

[Andreas Beckmann]

On 27/07/2024 16.20, Drew Parsons wrote:
> glx-diversions diverts /usr/lib/x86_64-linux-gnu/libGL.so to
> /etc/alternatives/glx--libGL.so-x86_64-linux-gnu which can be
> controlled by update-glx --config glx.

The libGL.so.* diversion is only relevant for the no longer supported 
legacy drivers up to 418.* that still exist in sid. These are the 
version where nvidia shipped vendor specific libGL.so.*. Newer drivers 
use glvnd, thus the alternatives are pointing to the diverted libglvnd 
libraries, not to vendor libraries. libGLX.so.* only comes with 
libglvnd, so there was no point to include that into the diversions.
(But as long as we keep the legacy drivers in sid (there are still users 
needing them for legacy ahrdware), we cannot get rid of the diversions.

> I think this explains why the nvidia drivers are not working in
> OFFLOAD (optimus) mode, e.g.

That must have some other cause.

> $ __NV_PRIME_RENDER_OFFLOAD=1  __GLX_VENDOR_LIBRARY_NAME=nvidia __VK_LAYER_NV_optimus=NVIDIA_only  glxinfo
> name of display: :0
> X Error of failed request:  BadValue (integer parameter out of range for operation)
>    Major opcode of failed request:  152 (GLX)
>    Minor opcode of failed request:  24 (X_GLXCreateNewContext)
>    Value in failed request:  0x0
>    Serial number of failed request:  50
>    Current serial number in output stream:  51
> 
> 
> I suspect this error would not occur if libGLX.so was diverted (given
> an alternative) to libGLX_nvidia.so.0
> (handled by update-glx --config glx, ultimately
> /usr/lib/x86_64-linux-gnu/nvidia/current/libGLX_nvidia.so.0
> from libglx-nvidia0)

libGLX_nvidia.so.0 is not a replacement for libGLX.so.*, it is rather an 
implementation that can be loaded by the libglvnd libGLX.so.0

> For what it's worth, nvidia now provides a fully supported open source kernal
> module, nvidia-open-kernel-dkms, so the nvidia driver is essentially no
> longer non-free. Please help them complete this change of policy by
> supporting use of the driver.

Only the kernel module has source available, all other driver components 
are closed source and thus non-free.

Andreas