Update README.md

README.md

@@ -3,20 +3,24 @@ Workaround for Linux throttling issues on Lenovo T480 / T480s / X1C6 notebooks a
 
 This script forces the CPU package power limit (PL1/2) to **44 W** (29 W on battery) and the temperature trip point to **97 'C** (85 'C on battery) by overriding default values in MSR and MCHBAR every 5 seconds (30 on battery) to block the Embedded Controller from resetting these values to default.
 
+The script now also supports **undervolting** the CPU by configuring voltage offsets for CPU, cache, GPU, System Agent and Analog I/O planes. The script will re-apply undervolt on resume from standby and hibernate by listening to DBus signals.
+
 ## Requirements
-The python module `python-periphery` is used for accessing the MCHBAR register by memory mapped I/O. 
+The python module `python-periphery` is used for accessing the MCHBAR register by memory mapped I/O. You also need `dbus` and `gobject` python bindings for listening to dbus signals on resume from sleep/hibernate.
 
 ## Installation
 ```
 git clone https://github.com/erpalma/lenovo-throttling-fix.git
 sudo -H pip install python-periphery
+sudo apt install python-dbus python-gobject
 sudo make install
 sudo systemctl enable lenovo_fix.service
 sudo systemctl start lenovo_fix.service
 ```
 
 ## Configuration
-The configuration has moved to `/etc/lenovo_fix.conf`. Makefile does not overwrite your previous config file, so you need to manually check for differences in config file structure when updating the tool. If you want to overwrite the config with new defaults just issue `sudo cp etc/lenovo_fix.conf /etc`. There exist two profiles `AC` and `BATTERY` and the script can be totally disabled by setting `Enabled: False` in the `GENERAL` section. All fields accept floating point values as well as integers.
+The configuration has moved to `/etc/lenovo_fix.conf`. Makefile does not overwrite your previous config file, so you need to manually check for differences in config file structure when updating the tool. If you want to overwrite the config with new defaults just issue `sudo cp etc/lenovo_fix.conf /etc`. There exist two profiles `AC` and `BATTERY` and the script can be totally disabled by setting `Enabled: False` in the `GENERAL` section. Undervolt is applied if any voltage plane in the config file (section UNDERVOLT) was set. Notice that the offset is in *mV* and only undervolting (*i.e.* negative values) is supported.  
+All fields accept floating point values as well as integers. 
 
 ## Disclaimer
 This script overrides the default values set by Lenovo. I'm using it without any problem, but it is still experimental so use it at your own risk. This script can be probably adapted/used on other notebooks too.