Re: [Linux-fbdev-devel] [PATCH] aty128fb 15/16 bit cleanup

[Michel <mic...@ii...>]

Sven LUTHER wrote:
> 
> On Wed, Jun 27, 2001 at 11:18:07PM +0200, Michel Dänzer wrote:
> > Sven LUTHER wrote:
> > > But again, X actually thinks that they are responsible for handling the
> > > card, and the DRI follows their lead. It is the X driver who handles the
> > > switch between the 2D and various 3D contexts.
> >
> > That's not correct. In the DRI context, the X server is one of many
> > clients the DRM mediates hardware access between.
> 
> mmm, but itis the X driver which fournish the register save/restore routins,
> at least that is how i see it. True it is the drm who calls them, i think,
> but still, if you have no X running, i don't know how the save/restore stuff
> is handled.

This is also getting shaky ground for me, but AFAIK each client of the DRM is
responsible to maintain its own context.

> I suppose you could have any user app initializing the drm with the
> contec=xt swithc function, but X and drm are very thigly intertwined.

There must be special communication between the X server and its clients
because they need to know where the windows are etc.

> Also, it seems the drm modules (or builtins) know really nothing about the
> underlaying hardware, it is the X server who tells them where the chip is,
> and what kind of chip to use.

Nope, the DRM finds the chip on its own. Just load the module and watch its
output.


> > > How will using hardware access on the console handle this ?
> >
> > I imagine fbcon would have to be a client of the DRM as well.
> 
> Sure, but will it not conflict with X ? DRI was built with 1 2D client and
> multiple 3d client in mind. I don't think it will run with more than 1 D2
> client right now.

Sure, the status quo is that when switching away from the X VT, the X server
grabs the hardware lock, thus preventing any other client from banging the
hardware. That would have to be changed, which makes this ever happening quite
a bit less probable, given that the console system on other OSs can't do the
same.

At any rate, this will have to be discussed with the major DRI hackers. The
address is dri...@li... . :)


-- 
Earthling Michel Dänzer (MrCooper)    \   Debian GNU/Linux (powerpc) developer
CS student, Free Software enthusiast   \        XFree86 and DRI project member