nixos-hardware/dell/xps/15-7590/README.md

# Dell XPS 15 7590
- Mostly copied from 15-9550

## Tested Hardware

- CPU: Intel(R) Core(TM) i9-9980HK
- RAM: 32 GB
- HDD: 1 TiB SSD
- Screen: 15" 4k (3840✕2160)
- Input: Touchscreen and trackpad.

## Firmware Configuration 

Not much tweaking of NixOS itself was needed. But we currently cannot automate the firmware setup, so this must be done by hand.

### Before installation

These settings are needed both for booting the final install, and installer itself. Therefore, they must be done first.

- **Disable Secure Boot (but keep UEFI Boot).** Thankfully doing so is as easy as changing any other simple setting.

- **Disable Intel hardware RAID and use AHCI instead.** Intel doesn't seem to provide a working linux driver for this.  (If you just have SSD it's pointless and just slows things down needlessly anyways.)

### Wifi
**Wifi does not work with kernels older than 5.1 (firmware not present) or newer** (https://bbs.archlinux.org/viewtopic.php?id=247705)

Update: The 48.ucode causes the Killer wifi card to crash. The iwlfwifi-cc-a0-46.ucode works perfectly. default.nix contains an overlay that removes the offending ucode from the linux-firmware bundle.

```
  # Use the systemd-boot EFI boot loader.
  boot.loader.systemd-boot.enable = true;
  boot.loader.grub = {
    device = "nodev";
    efiSupport = true;
    efiInstallAsRemovable = true;
  };
  boot.loader.efi.canTouchEfiVariables = true;
  boot.kernelPackages = pkgs.linuxPackages_5_1;
```
Disable the `canTouchEfiVariables` after a boot or two to prevent NVRAM wearout.


### After installation

- **Add systemd-boot to UEFI boot list.** The (uneditable anyways) settings mapping drive UUIDs to HD* work fine.

### Optional

- **Update BIOS.** According to Reddit, this helps with battery life.