Re: [PATCH 6/8] fbcon/fbdev: Remove fbc

["Antonino A. Daplas" <adaplas@hotpop.com>]

On Tuesday 02 November 2004 19:46, Petr Vandrovec wrote:
> On  2 Nov 04 at 19:46, Antonino A. Daplas wrote:
> > diff -Nru a/drivers/video/matrox/matroxfb_base.c
> > b/drivers/video/matrox/matroxfb_base.c ---
> > a/drivers/video/matrox/matroxfb_base.c  2004-10-23 02:52:37 +08:00 +++
> > b/drivers/video/matrox/matroxfb_base.c  2004-11-01 08:32:54 +08:00 @@
> > -1877,16 +1876,21 @@
> >     }
> >     printk("fb%d: %s frame buffer device\n",
> >            ACCESS_FBINFO(fbcon.node), ACCESS_FBINFO(fbcon.fix.id));
> > -   if (ACCESS_FBINFO(fbcon.currcon) < 0) {
> > -       /* there is no console on this fb... but we have to initialize
> > hardware -        * until someone tells me what is proper thing to do */
> > -       printk(KERN_INFO "fb%d: initializing hardware\n",
> > -           ACCESS_FBINFO(fbcon.node));
> > -       /* We have to use FB_ACTIVATE_FORCE, as we had to put
> > vesafb_defined to the fbcon.var -        * already before, so
> > register_framebuffer works correctly. */ -       vesafb_defined.activate
> > |= FB_ACTIVATE_FORCE;
> > -       fb_set_var(&ACCESS_FBINFO(fbcon), &vesafb_defined);
> > -   }
> > +   /*
> > +    * Tony: If this driver is to be mapped to the console, then
> > +    *       fbcon will automatically do a set_par for us.  The code
> > below +    *       may not be needed.
> > +    */
>
> Code below (which you made unconditional now) was executed if and only if
> there is no fbcon attached to this device.  If there is fbcon attached
> to this device, fbcon.currcon would be >= 0 after register_framebuffer()
> (and fbcon's startup already did needed set_*).  If there is no fbcon,
> this adapter is secondary, and it must be initialized too before leaving
> driver.  But it must not be initialized before call to
> register_framebuffer, as otherwise taking over vgacon won't work correctly.
>
> You could put some 'ACCESS_FBINFO(flags.hw_initialized) = 1' somewhere
> into matroxfb's set_par and then test this flag instead of fbcon.currcon.
>
> But your current code probably does not work very well on primary adapter.

Why not just leave the hardware uninitialized after register_framebuffer? Then,
initialize it at the first call to xxxfb_open()?  We can even check a
flag so we do this only once. This way if people accidentally enabled
matroxfb but forgot to enable fbcon, they will still get a usable vga
console.

Tony




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