Re: how to activate X with famebuffer

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

On Tuesday 28 September 2004 19:27, Mukund JB. wrote:
>
> ACCORDING TO FRAMEBUFFER DEFINITION :-
> A framebuffer device is an abstraction for the graphic hardware. It
> represents the frame buffer of some video hardware, and allows application
> software to access the graphic hardware through a well−defined interface,
> so that the software doesn't need to know anything about the low−level
> interface stuff
>
> This is taken from Geert Uytterhoeven's framebuffer.txt in the linux kernel
> sources. In the above definition what is an Application? Is it the X
> server, Applications above it?

'Application' is any process, user or kernel, that directly runs on top of the 
framebuffer. It can be X, or the framebuffer console.  It can be a process 
that totally bypasses X, such as directfb or mplayer -vo fbdev. Any process 
that does not run directly on top of the framebuffer is not considered as 
part of the 'Application' layer, such as kwrite on X on fbdev, or 'mplayer 
-vo directfb' on directfb on fbdev.

But X on fbdev or direcfb on fbdev or mplayer on fbdev are all considered part 
of the 'Application' layer.

>
> Suppose there is a kwrite application, obviously running over X server.
> Looking at this angle the flow is as follows:-
>
>
> 	NORMAL Applications ( Kwrite)
> 	-------------------
> 		X Server
> 	-------------------
> 	Framebuffer Driver
> 	-------------------
> 		HARDWARE
>

Yes, above is how it works.  In this case, Kwrite doesn't know a thing about 
the framebuffer, as it runs on top of X.  Or more properly, something like 
this:

NORMAL Applications such as X, DirectFB, mplayer, etc
-------------------
Framebuffer Driver
-------------------
HARDWARE

The X server is considered as part of 'NORMAL Applications'.

> Is it Applications like Kwrite should support Framebuffer in order the X
> server makes use of it. If this is the case, the flow will be as follows:-
>
> 	NORMAL Applications (Apps instructs X server - Use fb or don't use)
>    -------------------------
> 		X Server
>    -------------------------
> Framebuffer / NON-Framebuffer
> 		 Driver
>    -------------------------
> 		HARDWARE

No, the above is not the case.

Tony




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