Linux Intel FB Question

Linux Intel FB Question

[Justin Ducote]

Hi guys..

I would like to use the RADEON frame buffer, with
that said I am restricting this senario to the VESA
driver ONLY to try and clear up some of my confusion..

When I boot linux/grub (Redhat 9.0) with the following
line:

vga=792

Everything works great, I get 1024x768x16m and it uses
the VESA Framebuffer (I think) and everything is
great. 

If I try and use this line instead:

video=vesa:mode:1024x768-24@60

NOTHING happens.. 

My understanding was that those two
lines should yield the exact same result in theory. I
thought they are doing the same thing but the video
line does nothing so I am confused and I do not
understand whats going on. 

Additionally, 
I would like to know what is the relationship
between VGA= and VIDEO= 

Thank you for your time.
Justin Ducote

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Re: Linux Intel FB Question

[Geert Uytterhoeven]

On Mon, 14 Apr 2003, Justin Ducote wrote:
> I would like to use the RADEON frame buffer, with
> that said I am restricting this senario to the VESA
> driver ONLY to try and clear up some of my confusion..
> 
> When I boot linux/grub (Redhat 9.0) with the following
> line:
> 
> vga=792
> 
> Everything works great, I get 1024x768x16m and it uses
> the VESA Framebuffer (I think) and everything is
> great. 
> 
> If I try and use this line instead:
> 
> video=vesa:mode:1024x768-24@60
> 
> NOTHING happens.. 
> 
> My understanding was that those two
> lines should yield the exact same result in theory. I
> thought they are doing the same thing but the video
> line does nothing so I am confused and I do not
> understand whats going on. 
> 
> Additionally, 
> I would like to know what is the relationship
> between VGA= and VIDEO= 

`vga=' is a way to tell the early boot code in the kernel (before the actual
Linux kernel is started) to change the video mode using the BIOS.

`video=' is a way to pass initialization parameters to a frame buffer device
driver, or to just specific the default video mode (yes, `video=1024x768-24@60'
is OK).

Since vesafb relies on the BIOS setting up the correct video mode, the second
method won't work with vesafb.

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: Linux Intel FB Question

[Justin Ducote]

Hi Geert! 

> `vga=' is a way to tell the early boot code in the
> kernel (before the actual
> Linux kernel is started) to change the video mode
> using the BIOS.
> 
> `video=' is a way to pass initialization parameters
> to a frame buffer device
> driver, or to just specific the default video mode
> (yes, `video=1024x768-24@60'
> is OK).
> 
> Since vesafb relies on the BIOS setting up the
> correct video mode, the second
> method won't work with vesafb.
> 
> Gr{oetje,eeting}s,

Ok, I have a few more questions. I think I understand
a lot better now but:

1.) what is the syntax of the video line, I have seen
all kinds of examples on the net like:

"video=radeonfb:mode:1024x768-60@8"
"video=radeonfb:mode:1024x768-8@60"
"video=mode:1024x768-8@60"
"video=mode:1024x768-60@8"
"video=mode:1024x768"

sometimes with the drivername, sometimes without,
someimtes with a hypen and then the refresh rate
followed by a pound and then an @ symbol then the bpp
and vice versa. 

Is there a standardized syntax for the video line ? Do
you have to include the word "mode" what is the order
of information you have to provide, etc... 

How are these values interpreted and what order does
it read these values in ? What ist he format for
specifying pixel depth and refresh rate, etc. 

And is it possible to use vga= and video= together? 

video=radeonfb and then vga=792 

then my question is how does it know what refresh rate
and what pixed depth to use if you only use "vga=792"
?

I think I am close to having this figured out

Thanks for all the help
Justin


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Re: Linux Intel FB Question

[Geert Uytterhoeven]

On Tue, 15 Apr 2003, Justin Ducote wrote:
> 1.) what is the syntax of the video line, I have seen
> all kinds of examples on the net like:
> 
> "video=radeonfb:mode:1024x768-60@8"
> "video=radeonfb:mode:1024x768-8@60"
> "video=mode:1024x768-8@60"
> "video=mode:1024x768-60@8"
> "video=mode:1024x768"
> 
> sometimes with the drivername, sometimes without,
> someimtes with a hypen and then the refresh rate
> followed by a pound and then an @ symbol then the bpp
> and vice versa. 
> 
> Is there a standardized syntax for the video line ? Do
> you have to include the word "mode" what is the order
> of information you have to provide, etc... 
> 
> How are these values interpreted and what order does
> it read these values in ? What ist he format for
> specifying pixel depth and refresh rate, etc. 

See linux/Documentation/fb/modedb.txt.

> And is it possible to use vga= and video= together? 
> 
> video=radeonfb and then vga=792 

I don't think that's very useful.

> then my question is how does it know what refresh rate
> and what pixed depth to use if you only use "vga=792"
> ?

That depends on the BIOS, I think.

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: Linux Intel FB Question

[Sven Luther]

On Tue, Apr 15, 2003 at 01:09:12PM +0200, Geert Uytterhoeven wrote:
> On Tue, 15 Apr 2003, Justin Ducote wrote:
> > 1.) what is the syntax of the video line, I have seen
> > all kinds of examples on the net like:
> > 
> > "video=radeonfb:mode:1024x768-60@8"
> > "video=radeonfb:mode:1024x768-8@60"
> > "video=mode:1024x768-8@60"
> > "video=mode:1024x768-60@8"
> > "video=mode:1024x768"
> > 
> > sometimes with the drivername, sometimes without,
> > someimtes with a hypen and then the refresh rate
> > followed by a pound and then an @ symbol then the bpp
> > and vice versa. 
> > 
> > Is there a standardized syntax for the video line ? Do
> > you have to include the word "mode" what is the order
> > of information you have to provide, etc... 
> > 
> > How are these values interpreted and what order does
> > it read these values in ? What ist he format for
> > specifying pixel depth and refresh rate, etc. 
> 
> See linux/Documentation/fb/modedb.txt.
> 
> > And is it possible to use vga= and video= together? 
> > 
> > video=radeonfb and then vga=792 
> 
> I don't think that's very useful.

Its not possible to have vesafb on one card and anothe fb on anther card
then ?

Friendly,

Sven Luther


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Re: Linux Intel FB Question

[Geert Uytterhoeven]

On Tue, 15 Apr 2003, Sven Luther wrote:
> On Tue, Apr 15, 2003 at 01:09:12PM +0200, Geert Uytterhoeven wrote:
> > On Tue, 15 Apr 2003, Justin Ducote wrote:
> > > And is it possible to use vga= and video= together? 
> > > 
> > > video=radeonfb and then vga=792 
> > 
> > I don't think that's very useful.
> 
> Its not possible to have vesafb on one card and anothe fb on anther card
> then ?

Yes, that should be possible. As long as the vesafb one is the primary one.

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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