OpenDeviceDaemon, reinventing the wheel?

[Nils Faerber]

Hi!
First of all let me briefly introduce myself... I am working for GPE
Phone Edition[1] and LiPS[2] and have been working for Nokia/Maemo and
other mobile Linux projects for quite some time...

That being said I would like to raise a question about the "Open Device
Daemon" proposed... first on the Wiki page I found:
	"Support the freedesktop.org Open Device API standard via dbus"

But on freedesktop.org I cannot find that standard. I assume that this
is a typo and shall mean "freesmartphone.org Open Device API standard..."?

If this is the case I wonder if this is a good idea...
There is already a widely used and established API for more or less
exactly that purpose, i.e. providing a standardised DBus based API to
control and manage hardware, namely this is HAL[3].

Well, there is not only light about HAL, admittedly, but at least it
already provides the DBus API we are all looking for. The biggest
drawback of the current HAL implementation is its size at runtime - it
consumes large amounts of RAM and also spawns off a lot of child
processes. The advantage of HAL is that the API is quite well defined,
already existing for quite some hardware classes and that it is already
used by quite some other interesting projects, namely like OHM[4] but
also others like the Gnome network manager (well, we probably do not
want to use this directly on a phone but something similar).

HAL/OHM are also used and pushed by Nokia for the Maemo devices and are
also used on the OLPC.


For for the Device Management I would thus suggest to at least reuse and
extend where necessary the HAL API in order to stay compatible with e.g.
OHM.

Concerning implementation I would suggest to first have a deeper look at
the current HAL implementation and try to figure out why it is bad (we
know it is but we should be able to be more precise ;) and try to figure
out whether or not it can be improved. Based on that assessment we can
either start to work on HAL and bash it fit or start a fork of it,
something like µHAL probably (this is coming up every quarter of a year
but noone did it yet).
Rob Taylor did quite some work on slimming HAL, so we should probably
also try to get him in the loop as well.


Maybe I have also completely misunderstood the point here, so please
feel free to bring me back on track ;)


And then we also should talk about device policy management, that is
waht OHM is about... this is increadibly important for mobile devices
and is very closely realted to the device management...


[1] http://gpephone.linuxtogo.org
[2] http://www.lipsforum.org
[3] http://www.freedesktop.org/wiki/Software/hal
[4] http://ohm.freedesktop.org/wiki/

Cheers
  nils faerber

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