Client applications don't need to explicitly start the mm-control service before performing
media operations. The QNX CAR platform uses the System Launch Monitor (SLM) service to start
mm-control during bootup; this ensures mm-control is running when the HMI loads and users
begin interacting with its applications. For recovery purposes, applications can start mm-control manually.
Starting mm-control with specific command options during bootup
SLM automates process management by launching processes in an order that respects their interprocess dependencies.
The list of processes to launch and their properties, including their command-line arguments and interprocess dependencies,
is written in a configuration file. During bootup, SLM reads this file and carries out its instructions
for starting processes.
Using SLM to start mm-control ensures that the system is ready to process media commands
when the HMI finishes loading. For more information on SLM, refer to "System Launch and Monitor (SLM)" in
the System Services Reference.
SLM is preconfigured to start mm-control with specific command
options, but you can specify whatever command options you want.
To change the command options passed by SLM to mm-control:
-
From a command console connected to your car system,
navigate to and open the SLM configuration file, whose default path is:
/etc/slm-config-all.xml.
-
In the configuration file, locate the
component that specifies the properties for
mm-control.
This component is the
<SLM:component> XML object with the name
"mmcontrol".
-
Change the value of the <SLM:args> tag in the
"mmcontrol" component to hold the new set of command-line
options to pass to mm-control at startup.
-
Save the changes to the SLM configuration file and return to the console.
-
If you want the new configuration to take effect immediately,
enter reboot in the console.
The system reboots and the SLM utility relaunches all the processes,
including
mm-control, with the command options
specified in the configuration file. When the system finishes reloading,
mm-control is running with the new configuration.
If you don't reboot after changing the configuration file,
mm-control continues to run with its previous configuration
until you shut down the system and restart, at which point the new command
options take effect.