This fixes a harmless error from systemd-udevd that looks like:
Dec 23 15:35:23 dellbook systemd-udevd[696]:
/nix/store/iixya3ni5whybpq9zz1h7f4pyw7nhd19-udev-rules/99-local.rules:25
Invalid value "..." for RUN (char 101: invalid substitution type),
ignoring, but please fix it.
Using $$ fixes it using the escaping documented at https://www.freedesktop.org/software/systemd/man/udev.html.
The SLIM project is abandoned and their last release was in 2013.
Because of this it poses a security risk to systems, no one is working
on it or picked up maintenance. It also lacks compatibility with systemd
and logind sessions. For users, there liikely isn't anything like slim
that's as lightweight in terms of dependencies.
Invoke xrandr to actually connect the device.
Additionally, we let systemd create the logs directory and use our module loader
instead of handling it manually.
A new internal option `hardware.opengl.setLdLibraryPath` is added which controls if `LD_LIBRARY_PATH` should be set to `/run/opengl-driver(-32)/lib`. It is false by default and is meant to be set to true by any driver which requires it. If this option is false, then `opengl.nix` and `xserver.nix` will not set `LD_LIBRARY_PATH`.
Currently Mesa and NVidia drivers don't set `setLdLibraryPath` because they work with libglvnd and do not override libraries, while `amdgpu-pro`, `ati` and `parallels-guest` set it to true (the former two really need it, the last one doesn't build so is presumed to).
Additionally, the `libPath` attribute within entries of `services.xserver.drivers` is removed. This made `xserver.nix` add the driver path directly to the `LD_LIBRARY_PATH` for the display manager (including X server). Not only is it redundant when the driver is added to `hardware.opengl.package` (assuming that `hardware.opengl.enable` is true), in fact all current drivers except `ati` set it incorrectly to the package path instead of package/lib.
This removal of `LD_LIBRARY_PATH` could break certain packages using CUDA, but only those that themselves load `libcuda` or other NVidia driver libraries using `dlopen` (not if they just use `cudatoolkit`). A few have already been fixed but it is practically impossible to test all because most packages using CUDA are libraries/frameworks without a simple way to test.
Fixes#11434 if only Mesa or NVidia graphics drivers are used.
This adds configuration options which automate the configuration of NVIDIA Optimus using PRIME. This allows using the NVIDIA proprietary driver on Optimus laptops, in order to render using the NVIDIA GPU while outputting to displays connected only to the integrated Intel GPU. It also adds an option for enabling kernel modesetting for the NVIDIA driver (via a kernel command line flag); this is particularly useful together with Optimus/PRIME because it fixes tearing on PRIME-connected screens.
The user still needs to enable the Optimus/PRIME feature and specify the bus IDs of the Intel and NVIDIA GPUs, but this is still much easier for users and more reliable. The implementation handles both the X configuration file as well as getting display managers to run certain necessary `xrandr` commands just after X has started.
Configuration of commands run after X startup is done using a new configuration option `services.xserver.displayManager.setupCommands`. Support for this option is implemented for LightDM, GDM and SDDM; all of these have been tested with this feature including logging into a Plasma session.
Note: support of `setupCommands` for GDM is implemented by making GDM run the session executable via a wrapper; the wrapper will run the `setupCommands` before execing. This seemed like the simplest and most reliable approach, and solves running these commands both for GDM's X server and user X servers (GDM starts separate X servers for itself and user sessions). An alternative approach would be with autostart files but that seems harder to set up and less reliable.
Note that some simple features for X configuration file generation (in `xserver.nix`) are added which are used in the implementation:
- `services.xserver.extraConfig`: Allows adding arbitrary new sections. This is used to add the Device section for the Intel GPU.
- `deviceSection` and `screenSection` within `services.xserver.drivers`. This allows the nvidia configuration module to add additional contents into the `Device` and `Screen` sections of the "nvidia" driver, and not into such sections for other drivers that may be enabled.
