Update README.md

thinkpad/x250: add acpi_call

This kernel module is needed to, for example, support tlp's

  - `START_CHARGE_THRESH_BAT?` and
  - `STOP_CHARGE_THRESH_BAT?`

options.

thinkpad: minor trackpoint fixes

Add better pulseaudio support for thinkpad t490

At first (till third glance) I thought only the listed profiles are supported

Newer ThinkPads have a new name for the Trackpoint - "TPPS/2 Elan TrackPoint".

Having the "[...] IBM Trackpoint" as default caused some weird
side-effects on my machine (e.g. stopped the trackpoint working after a
suspend) with the wrong name. Although this is mentioned in the option's
description[1], I think that this should be declared explicitly here.

As soon, as we supported newer models as well[2], we should probably
move this into its own common profile.

[1] https://nixos.org/nixos/options.html#hardware.trackpoint.device
[2] https://certification.ubuntu.com/catalog/component/input/5313/input%3ATPPS/2ElanTrackPoint/

Most trackpoint users I know use the middle-button to have some
scrolling functionality. So I think that for ThinkPads at least we
should have this enabled by default if the trackpoint shall be used.

toshiba/swanky: switch to default kernels

enable fstrim on SSDs

This will run TRIM once a week using a systemd timer. Running TRIM regularly
will improves the performance and increases the SSDs lifespan. Since it is based
on the utillinux no additional package is required.

Specify a correct unit description

Both unstable and 19.03 come with 4.19+ kernels
making this option obsolete.

dell/xps/13-9380: also import intel profile

t430: add acpi_call module

Added basic support for the t470s

And reorder other XPS 13.

pcengines/apu: expose GRUB over serial

Prior to this commit, an apu's boot would go through stages of varying visibility:
1. BIOS: exposed to serial
2. GRUB: not exposed to serial
3. Linux: exposed to serial

This commit changes (2) to be visible over serial, so the entire boot is visible over serial.

Tested on nixos 18.09 on a https://www.pcengines.ch/apu1d.htm

lenovo-x1: removed battery TLP threshholds

This is pretty much a copy of XPS 9370, without kaby-laky and the throttle bug. I was getting lockups with the kaby-laky changes and the throttle bug did not seem to have an impact either way.

add dummy default.nix

fix nix-env evaluation

nix-env picked up `default.nix`, which contained our hardware profiles.
This is not only cpu-intensive to evaluate but also fails because
it does some import-from-derivation.
By moving default.nix to release.nix it should be no longer loaded

lenovo x1 carbon gen6: update S3 suspend

With UEFI >= 1.30, there's an explicit option to enable S3 power management.
Once this is selected, S3 is enabled and "deep" is selected as the default
/sys/power/mem_sleep value without requiring any kernel boot parameters.

This adds basic support for the Thinkpad T440s, based on the work done for the T440p. The expression enables:

- microcode updates
- trackpoint support
- kernel module for battery level management

common/cpu: default microcode updates to enableRedistributableFirmware

copy of #81