Lenovo ThinkPad X1 Yoga (Gen 5)
In August of 2018 Lenovo has joined the Linux Vendor Firmware Service (LVFS) project, which enables firmware updates from within the OS. BIOS updates (and possibly other firmware such as the Thunderbolt controller) can be queried for and installed through fwupd.
The BIOS has two "Sleep State" options, called "Windows" and "Linux", which you can find in at
Config -> Power -> Sleep State. The Linux option is the traditional S3 power state where all hardware components are turned off except for the RAM, and it should work normally. The Windows option is a newer software-based "modern standby" which works on Linux (despite the name). One possible benefit to the Windows sleep state is faster wake up time, and one possible drawback is increased power usage.
Reboot and verify whether S3 is working by running:
# dmesg | grep -i "acpi: (supports"
You should now see something like this:
[ 0.230796] ACPI: (supports S0 S3 S4 S5)
This laptop requires firmware in order for the soundcard to work. See Advanced Linux Sound Architecture#ALSA firmware.
The kernel parameter
snd_hda_intel.dmic_detect=0 is required in order to have working speakers.
|Fn+Space||toggle keyboard backlight|
|Fn+L||"low power mode"|
|Fn+M||"normal power mode"|
|Fn+H||"high power mode"|