Lenovo ThinkPad SL500
The support for this laptop is not as bad as it first seems. In fact, pretty much everything works fine. I am very happy with this machine!
While this guide if for the Thinkpad SL500, the steps should be easily applicable to the SL300 and SL400 models.
Despite the Thinkpad name, the SL series laptops actually contain IdeaPad firmware, making it incompatible with the thinkpad_acpi modules. A new module, lenovo-sl-laptop has been written to expose most of the lost functionality. Thinkwiki has a page for the SL series with good general information and howtos.
Getting the wireless to work is relatively easy. Following the wireless setup guide should suit your needs.
lenovo-sl-laptop Kernel Module
EDIT: These modules are no longer required in 2.6.32, use the mainline asus-laptop module, it works just as good.
This experimental kernel module was written to control bluetooth, hotkeys, fan, and screen brightness in place of the incompatible thinkpad_acpi module. A package is currently available in the AUR. After installation, be sure to load the module, and to load on startup, add lenovo-sl-laptop to the MODULES array in rc.conf.
Despite it's experimental status, it works quite well. Sadly, there is no support for the HDAPS.
To allow control of the backlight, first edit /etc/modprobe.d/modprobe.conf as follows:
options lenovo-sl-laptop control_backlight=1
Then turn off ACPI control of the backlight by performing the command on startup.
echo 0 > /sys/module/video/parameters/brightness_switch_enabled
A preferable alternative is to add the following to your kernel boot line to do so on startup.
Instead of installing the AUR package, the module can built manually from source.
To do so, first obtain the source from here and perform the following
make sudo install -m=644 -D lenovo-sl-laptop.ko /lib/modules/`uname -r`/kernel/lenovo_sl_laptop/lenovo-sl-laptop.ko depmod -a modprobe lenovo-sl-laptop control_backlight=1
The bluetooth light on the front of your laptop should turn on.
Finally, add lenovo-sl-laptop to your MODULES array in your rc.conf.
USB and SD auto mounting
Check out the Udev rules for automounting USB and sd cards, very handy.
The SD card reader seems a bit buggy.
Fingerprint reader, Bluetooth, Modem.
Thread on the forums concerning configuration of Arch Linux on the SL series