Re: [Linux-fbdev-devel] Feature Freeze?

[James S. <jsi...@in...>]

> I have already a working fbcon module unloading code in my local copy. 
> The way it works is like this.  
> 
> 1. If take_over_console() is called with the "default" flag clear, it
> behaves as usual.  It takes only a subset of console numbers but
> "conswitchp" still points to the console driver that was loaded at boot
> time.
> 
> 2. If take_over_console() is called with the "default" flag set, it will
> replace "conswitchp", but the original value of "conswitchp" is saved.
> 
> 3.  If take_over_console() with the "default" flag set is called again,
> it will fail.  It's not logical to just overwrite "conswitchp" over and
> over again.
> 
> 4. If give_up_console() is called and if the previous
> take_over_console() did not overwrite "conswitchp", it proceeds as
> usual.
> 
> 5. If give_up_console() is called and if the previous
> take_over_console() overwrote "conswitchp", give_up_console() will also
> call take_over_console() but using the saved "conswitchp".
> 
> I can then load fbdev and fbcon as modules.  If I "rmmod fbcon", I get
> back again to vgacon/dummycon/whatever.  I can then load and unload
> different fbdev's and load fbcon at will.
> 
> If I want to load mdacon, it will still work on top of fbcon, because
> mdacon calls take_over_console() with the "default" flag cleared.
> 
> If you need to load other console drivers, then fbcon must be unloaded
> first.  This is because the rest of the console drivers call
> take_over_console() with the "default" flag set.
> 
> I can already load/unload fbcon using vga16fb, rivafb or i810fb as the
> backend at will.  Drivers that wish to allow fbcon unloading can define
> the xxxfb_release() method.  They can choose to save/restore the state
> (if they have a vga core and running as primary), or just define the
> xxfb_release method as a dummy (if no vga core or running as secondary).
> 
> What do you think?  Any suggestions to improve this (multiple console
> drivers for instance)? I would rather have the above, or disallow
> unloading, than having the whole console system freeze on me.

Send me the patch. I like to have this support. As for multiple console 
support. Well that will just be nasty. Nothing we can do about it.