Plugin ratings

Plugins rate themselves on their ability to obtain information from various device types and report their ratings to the plugin manager so that it can choose the best plugin for filling in data fields.

Each plugin provides two ratings of itself:
Support for a device publisher
The plugin indicates whether or not it supports the specified device publisher.
Information extraction ability
The plugin provides a numeric score indicating its ability to read device information. The plugin manager uses these scores to rank plugins against each other.
The following table shows which plugins work with each of the device publishers, with the plugins listed from highest rated to lowest rated:
Device publisher Supporting plugins
usblauncher_otg ipod, dvd, mediafs, audiocd, generic
mmcsdpub generic
cdpub dvd, audiocd, generic

Plugin selection

Although the plugin manager ranks the plugins based on their ability to extract information, the particular plugin used for filling in data fields also depends on the device type.

Suppose you connect a Media FS device through a USB port. If the USB launcher service requested the device name and ID, the plugin manager would first invoke the ipod plugin but this plugin would fail to fill in the fields because the device isn't an iPod. Next, the plugin manager would invoke mediafs, which would try to obtain the requested information. If that second plugin failed for whatever reason, the plugin manager would invoke generic. So, the extra device information can come from any plugin that supports the publisher.