Re: [Linux-fbdev-devel] Some questions

[Antonino D. <ad...@po...>]

On Thu, 2003-03-06 at 16:33, Geert Uytterhoeven wrote:
> On Wed, 5 Mar 2003, James Simmons wrote:
> > > > We should split the monitor programing stuff out from stuff like bpp etc.
> > > > Now if you think about it we can do things like change the bpp without 
> > > > having to redo the monitor programming. This is the flaw with the old and 
> > > > even the new api. 
> > > 
> > > You could have done that from the beginning. Just look at which fields have
> > > changed and which haven't.
> > 
> > I should of but didn't because I knew driver would take teh path of lest 
> > resistance to port there drivers. TO much change would have made the 
> > current situtation much much worst. 
> 
> One other reason why this isn't done is because X may interfere with it. If we
> don't do a full register update, but change the parts that need a change only,
> we will see less flickering (no PLL reprogramming), but we will suffer if X
> doesn't restore the registers to the exact same values they were before.
> 

Ideally, that is what should happen.  However, fb_set_var does a check
if the passed var is different from the default var.  If it's the same,
fb_set_par is skipped.  Switching back from X, this check will be mostly
false, so fb_set_par will be skipped, and register refreshing would have
failed.

So, I think fbcon should also detect if the previous console is not
fbcon (ie previous con > last_fbvc || previous con < first_fbvc), and if
it isn't, force an fb_set_par.

Tony