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From: "Antonino A. Daplas" <adaplas@hotpop.com>
Reply-To: adaplas@pol.net
To: Geert Uytterhoeven <geert@linux-m68k.org>
Subject: Re: [Linux-fbdev-devel] [PATCH 4/5][RFC] fbdev: Clean up framebuffer initialization
Date: Sun, 5 Sep 2004 18:40:10 +0800
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Cc: Linux Frame Buffer Device Development 
	<linux-fbdev-devel@lists.sourceforge.net>,
       Andrew Morton <akpm@osdl.org>,
       Linux Kernel Development <linux-kernel@vger.kernel.org>,
       Thomas Winischhofer <thomas@winischhofer.net>
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On Sunday 05 September 2004 18:13, Geert Uytterhoeven wrote:
> On Sun, 5 Sep 2004, Antonino A. Daplas wrote:
> > On Sunday 05 September 2004 17:16, Geert Uytterhoeven wrote:
> > > On Sat, 4 Sep 2004, Antonino A. Daplas wrote:
> > > > Currently, the framebuffer system is initialized in a roundabout
> > > > manner. First, drivers/char/mem.c calls fbmem_init().  fbmem_init()
> > > > will then iterate over an array of individual drivers' xxxfb_init(),
> > > > then each driver registers its presence back to fbmem.  During
> > > > console_init(), drivers/char/vt.c will call fb_console_init(). fbcon
> > > > will check for registered drivers, and if any are present, will call
> > > > take_over_console() in drivers/char/vt.c.
> > > >
> > > > This patch changes the initialization sequence so it proceeds in this
> > > > manner: Each driver has its own module_init(). Each driver calls
> > > > register_framebuffer() in fbmem.c. fbmem.c will then notify fbcon of
> > > > the driver registration.  Upon notification, fbcon calls
> > > > take_over_console() in vt.c.
> > >
> > > My main concern with this change is that it will be no longer possible
> > > to change initialization order (and hence choose the primary display
> > > for systems with multiple graphics adapters) by specifying
> > > `video=xxxfb' on the kernel command line.
> >
> > I see your point.  But, can we use "fbcon=" setup options to choose which
> > fb gets mapped to what console? We already have fbcon=map:<option> so we
> > can choose which becomes the primary display. Granted the "fbcon=" setup
> > is currently broken, but if fixed, will that be a fair compromise?
>
> Yes, sounds fine.

Thanks.

>
> Just thinking of something else: right now it's possible to disable a fbdev
> by saying `video=xxxfb:off'. This can be useful if the fbdev driver doesn't
> work with your hardware. After you change, individual fbdev drivers will
> have to reimplement this theirselves in their __setup() functions.

Yes.  I hope this doesn't bite too deep.  If it does, I think we can let
fb_get_options() return an error  when the "off" option is present.  But I'm
not going to implement it unless we get a lot of complaints.

Tony 


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