Re: [Lcd4linux-devel] Dynamic loading of drivers / plugins ?

[Michael R. <re...@eu...>]

Hi Xavier,

> I checked out the CVS from another machine with decent adsl internet
> acces, cfg_get() seems to work now. plugin_i2c_sensors will be soon
> finished ;)

Fine! But do a CVS checkout again, and regularly, because I'm changing a 
lot at the moment (which is bad for you and your GSM, but good for 
lcd4linux :-)

btw, I just added some "hash" utility functions, they work similar to 
the 'associative arrays' from perl. You can use them to store 
information gathered from various /proc files (I'm pointing at your xmms 
plugin). Take a look at plugin_cpuinfo.c, which parses /proc/cpuinfo, 
and you get an idea of how this could be done.

> I saw you're beginning a rewrite of LCDs drivers at the same time of
> plugins. One suggestion : shouldn't we think about so-ing all these
> plugins and drivers (and place them in /usr/lib/lcd4linux) so that
> lcd4linux can load only the driver(s) and plugins that are used, so it
> can consume a lot less memory ! Furthermore, with the debian packages,
> we shouldn't rely on compile-time options (dvb, X11, ...).

This is a very good idea! This came to my mind some months ago, but I 
forgot about it.

As I'm not familiar with dlopen() and friends, maybe someone out there 
wants to take a look at that?

> Automatic loading of LCDs driver will be somewhat easy to do as it's
> specified in the config file. I would be fast to implement.

That's right. But what about 'lcd4linux -l', which should list all 
drivers and models? :-(

> The case of plugins can be more problematic : how can the evaluator
> guess which .so it has to load, maybe an internal tree of functions
> provided by plugins asociated with a scan of functions evaluated. If the
> evaluator doesn't know a function it scans in the tree for the plugin
> providing this function. It won't produce a speed-down as the necessary
> plugins are loaded at the first loop (in the case of the config file,
> not interactive mode) and will permit IMHO more flexibility and consume
> less memory.

With plugins, I could think of loading all plugins which can be found in 
a directory, becausae they follow the naming scheme "plugin_*.so". The 
same technique could probably be used for the "list all drivers problem"


bye, Michael

-- 
Michael Reinelt                                   Tel: +43 676 3079941
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