Generic framebuffer driver

Generic framebuffer driver

[Otto Wyss]

Since I never could acceptable align my monitor screen between Windows,
Linux console and Linux X-server I bought a DVI cable and switch to
digital mode. Immediately I discovered a fantastic feature of the radeon
framebuffer driver, it's able to discover the correct resolution of my
LCD monitor.

I guess this is a common feature of the digital interface and might be
available for any graphic card/monitor with DVI. Does anyone know for
sure? If yes this feature would allow to create a generic framebuffer
driver which could be built into the kernel and used right from the
start. How nice would it be to have a shiny startup screen right from
the start of Linux! All the startup messages could be shown in a decent
font (maybe even configurable) and might be surrounded by a nice window.
What a difference would it make against the current DOS-like look.

The main task of this generic driver is to detect and switch to the
correct resolution and may only handle simple 2D drawing. It should only
support common features. It needs only be useful during startup and in
cases no specific framebuffer driver exists. And of course it has to
stop working and yield any resources when a card specific driver is loaded.

Do you also think such a generic driver should exist? Is anyone able to
create it, maybe simply extract it from the radeonfb?

O. Wyss

-- 
See a huge pile of work at "http://wyodesktop.sourceforge.net/"


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Re: Generic framebuffer driver

[Geert Uytterhoeven]

On Fri, 20 Aug 2004, Otto Wyss wrote:
> Since I never could acceptable align my monitor screen between Windows,
> Linux console and Linux X-server I bought a DVI cable and switch to
> digital mode. Immediately I discovered a fantastic feature of the radeon
> framebuffer driver, it's able to discover the correct resolution of my
> LCD monitor.
>
> I guess this is a common feature of the digital interface and might be
> available for any graphic card/monitor with DVI. Does anyone know for
> sure? If yes this feature would allow to create a generic framebuffer

It can work for normal monitors as well, using DDC.

> driver which could be built into the kernel and used right from the
> start. How nice would it be to have a shiny startup screen right from
> the start of Linux! All the startup messages could be shown in a decent
> font (maybe even configurable) and might be surrounded by a nice window.
> What a difference would it make against the current DOS-like look.

Like what e.g. SUSE does?

> The main task of this generic driver is to detect and switch to the
> correct resolution and may only handle simple 2D drawing. It should only
> support common features. It needs only be useful during startup and in
> cases no specific framebuffer driver exists. And of course it has to
> stop working and yield any resources when a card specific driver is loaded.
>
> Do you also think such a generic driver should exist? Is anyone able to
> create it, maybe simply extract it from the radeonfb?

This generic driver does not exist. And it's not simple to write, since it's
hardware dependent.

The closest thing to such a generic driver is the existing vesafb. Perhaps on
some cards the BIOS uses DDC as well to find a nice video mode?

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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Re: Generic framebuffer driver

[Otto Wyss]

Geert Uytterhoeven wrote:
> 
> On Fri, 20 Aug 2004, Otto Wyss wrote:
> > I guess this is a common feature of the digital interface and might be
> > available for any graphic card/monitor with DVI. Does anyone know for
> > sure? If yes this feature would allow to create a generic framebuffer
> 
> It can work for normal monitors as well, using DDC.
> 
Maybe, but then I'm wondering why it only works with DVI in the
radeonfb. Has anyone tried a DVI cable with other cards and can post information?

> > driver which could be built into the kernel and used right from the
> > start. How nice would it be to have a shiny startup screen right from
> > the start of Linux! All the startup messages could be shown in a decent
> > font (maybe even configurable) and might be surrounded by a nice window.
> > What a difference would it make against the current DOS-like look.
> 
> Like what e.g. SUSE does?
> 
Unfortunately I don't have Suse, is there link to an image? Anyway I
though more like the Mac, besides the Mac shows that such a solution is possible.

> > Do you also think such a generic driver should exist? Is anyone able to
> > create it, maybe simply extract it from the radeonfb?
> 
> This generic driver does not exist. And it's not simple to write, since it's
> hardware dependent.
> 
> The closest thing to such a generic driver is the existing vesafb. Perhaps on
> some cards the BIOS uses DDC as well to find a nice video mode?
> 
The vesafb proves that there is a common base for framebuffer driver.
IMO any card having a DVI plug also has to have a common protocol which
can be used for a generic driver without being too hardware dependent
and also without using BIOS calls. It might be possible to create such a
driver for all cards but it shouldn't be too difficult to create it for
i.e. 80%.

O. Wyss

-- 
See a huge pile of work at "http://wyodesktop.sourceforge.net/"


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Re: Generic framebuffer driver

[Geert Uytterhoeven]

On Sat, 21 Aug 2004, Otto Wyss wrote:
> Geert Uytterhoeven wrote:
> > On Fri, 20 Aug 2004, Otto Wyss wrote:
> > > Do you also think such a generic driver should exist? Is anyone able to
> > > create it, maybe simply extract it from the radeonfb?
> >
> > This generic driver does not exist. And it's not simple to write, since it's
> > hardware dependent.
> >
> > The closest thing to such a generic driver is the existing vesafb. Perhaps on
> > some cards the BIOS uses DDC as well to find a nice video mode?
> >
> The vesafb proves that there is a common base for framebuffer driver.
> IMO any card having a DVI plug also has to have a common protocol which
> can be used for a generic driver without being too hardware dependent
> and also without using BIOS calls. It might be possible to create such a
> driver for all cards but it shouldn't be too difficult to create it for
> i.e. 80%.

DVI is just the transport protocol to talk to the TFT. Graphics chips are still
initialized by the BIOS to VGA text mode.

You still need software to:
  - initialize the graphics chip to the video mode you want
  - program the DVI controller

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


-------------------------------------------------------
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