DOC: add --pm_by_vuart setting guide.
new params: --pm_by_vuart is used to set power mananger by vuart
on ACRN; so add it to user guide.
@@ -331,9 +331,27 @@ Here are descriptions for each of these ``acrn-dm`` command line parameters:
- This option is used to define which channel could be used DM to
communicate with VM about power management event.
- ACRN supports two channels: ``ioc`` and ``power button``.
+ ACRN supports three channels: ``ioc``, ``power button`` and ``uart``.
usage::
--pm_notify_channel ioc
Use ioc as power management event motify channel.
+
+ * - :kbd:`--pm_by_vuart [pty|tty],<node_path>`
+ - This option is used to set a user OS power management by virtual UART.
+ With acrn-dm UART emulation and hypervisor UART emulation and configure,
+ service OS can communicate with user OS through virtual UART. By this
+ option, service OS can notify user OS to shutdown itself by vUART.
+
+ It need work with `--pm_notify_channel` and PCI UART setting (lpc and -l).
+
+ Example::
+
+ for general UOS, like LaaG or WaaG, it need set:
+ --pm_notify_channel uart --pm_by_vuart pty,/run/acrn/life_mngr_vm1
+ -l com2,/run/acrn/life_mngr_vm1
+ for RTVM, like RT-Linux:
+ --pm_notify_channel uart --pm_by_vuart tty,/dev/ttyS1
+
+ For different UOS, it can be configured as needed.
