[vdr] how to display information on channel change?

[Luca Olivetti <luca@ventoso.org>]

I'm trying to write a plugin to drive a linear actuator (since it's what 
I have on my dish) through the parallel port.
I've already written a kernel module that's more or less working (I 
haven't built the hardware yet, but it's setting the output pins, 
counting pulses and stopping when it has reached the target position).

For the plugin part, since I'm no c++ coder, I'm "borrowing" from the 
rotor plugin (its operation is quite similar to what I'm going to need).
To move the dish it's using a status monitor: using ChannelSwitch, it 
checks if it's a different satellite, and if it is:

1) it tells my device driver the target position (the dish will start 
moving)
2) it opens an osd (cOsdProvider::NewOsd)
3) it displays that the dish is moving (I'd also like to display the 
current position in the following loop, but I haven't managed to do that 
yet)
4) it waits until the position has been reached (or there was an error) 
or a key is pressed
5) it closes the osd

The problem is that is disrupts the normal osd shown on channel change 
and eventually it crashes vdr (the xine plugin says "xineDevice.c:801: 
void PluginXine::cXineDevice::OnFreeOsd(cOsd*): Assertion `osd == 
m_currentOsd' failed.", I think that's been discussed recently in the 
thread "OSD: is it allowed to have multiple instances").

I have many doubts here:

a) How can I display that the dish is moving and its position without 
disrupting the normal osd and without crashing xine?

b) is there a better way to determine when it's time to move the dish or 
the status monitor is the correct hook?

c) is it correct not to return from ChannelSwitch until the dish has 
reached the position (or a key has been pressed)? If it isn't, how can I 
accomplish a)?

d) do you know of any free byte in the cmos ram whare I could store the 
current position? (ok, this one isn't strictly related to vdr and the 
osd, but the wizards that developed the cmos wake up program for vdr 
maybe know and are reading this list)


Bye
--
- Yo también quiero una Europa libre de Patentes de Software  -
- I want a Software Patents Free Europe too! And you?         -
---------------------------------------------------------------
  EuropeSwPatentFree - http://EuropeSwPatentFree.hispalinux.es

Attachment: signature.asc
Description: OpenPGP digital signature