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List:       linux-video
Subject:    [video4linux] Driver for ATI All-In-Wonder et al.
From:       Martin Pilaski <pilaski () mathi ! uni-heidelberg ! DE>
Date:       1998-06-16 15:33:51

Hi !

Unlike many others I was lucky enough to get the technical maunals  
from Ati. So I started to work on a driver yesterday. For the Bt829  
used by Ati has the same command-set as the Bt848 I expect to be  
able to use quite some lines from Ralph Metzlers bttv ( presumeing I  
understand his code ;) The main difference between Bt829 and Bt848  
is the host-interface ( PCI vs. I2C )

One major difficulty might be releasing the sourcecode, for the  
manuals are confidential and I had to sign some non-diclosure  
agreement. But from what some Ati-personell told me I expect them to  
agree with GPL. But that is not official yet.

After reading Alans API documentation I still have a question:  
Where inside the framebuffer can I put the ( temporary ) captured  
images that are to be scaled and then overlayed. As far as I  
understood VIDEOCSFBUFF tells me where and how large the framebuffer  
is but not wich area I may use, right ?!?

I hope to have something very curde that at least shows pictures  
shortly. If there is something releasable I will let you know.

key U

Martin
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List:       linux-video
Subject:    Re: [video4linux] Driver for ATI All-In-Wonder et al.
From:       Alan Cox <alan () cymru ! net>
Date:       1998-06-16 19:05:13
[Download message RAW]

> One major difficulty might be releasing the sourcecode, for the  
> manuals are confidential and I had to sign some non-diclosure  
> agreement. But from what some Ati-personell told me I expect them to  
> agree with GPL. But that is not official yet.

Well if you use any of the existing GPL'd code you will have to release
the software itself GPL or not at all. I suspect you'll be ok - 
confidential docs, non confidential code after approval is quite common

> Where inside the framebuffer can I put the ( temporary ) captured  
> images that are to be scaled and then overlayed. As far as I  
> understood VIDEOCSFBUFF tells me where and how large the framebuffer  
> is but not wich area I may use, right ?!?

It tells you were to land the final image. Right at the moment there is
no way to find where in the frame buffer to use for expansions. You'll
have to get into the Xserver side for that, and may need to get the X
folks to add hooks (for now lie about how much videoram you have ;))

> I hope to have something very curde that at least shows pictures  
> shortly. If there is something releasable I will let you know.

Good luck

Alan

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List:       linux-video
Subject:    Re: [video4linux] Driver for ATI All-In-Wonder et al.
From:       Martin Pilaski <pilaski () mathi ! uni-heidelberg ! DE>
Date:       1998-06-17 13:52:24

You wrote:
> > Where inside the framebuffer can I put the ( temporary ) captured
> > images that are to be scaled and then overlayed. As far as I
> > understood VIDEOCSFBUFF tells me where and how large the
> > framebuffer is but not wich area I may use, right ?!?
>
> It tells you were to land the final image. Right at the moment
> there is no way to find where in the frame buffer to use for
> expansions. You'll have to get into the Xserver side for that, and
> may need to get the X folks to add hooks (for now lie about how
> much videoram you have ;))
Is this buffer inside the area X uses as display memory ? This  
would mean I have to set VID_TYPE_OVERLAY and VID_TYPE_FRAMERAM and  
the buffer would have some strange layout ( bytesperline as  
mentioned in your API draft is larger than the the number of bytes  
in one frames line ). Did I get you right ?!?

key U

Martin
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List:       linux-video
Subject:    Re: [video4linux] Driver for ATI All-In-Wonder et al.
From:       Alan Cox <alan () cymru ! net>
Date:       1998-06-17 16:20:31

> Is this buffer inside the area X uses as display memory ? This  
> would mean I have to set VID_TYPE_OVERLAY and VID_TYPE_FRAMERAM and  
> the buffer would have some strange layout ( bytesperline as  
> mentioned in your API draft is larger than the the number of bytes  
> in one frames line ). Did I get you right ?!?

The OVERLAY|FRAMERAM is meant for devices which DMA or otherwise write
directly into image memory. Devices that overlay by chromakey are 
not going to need it. Devices that work by copying the image at a fixed
size and format into offscreen space arent really covered right now as
we have no way to tell the Xserver 'give me a rectangle of video ram'.

Theres been some discussion of these issues with the XFree people and
hopefully 4.0 will address a lot of this stuff.
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List:       linux-video
Subject:    Re: [video4linux] Driver for ATI All-In-Wonder et al.
From:       Martin Pilaski < pilaski () vogon ! mathi ! uni-heidelberg ! DE>
Date:       1998-06-17 18:13:43

On Wed, 17 Jun 1998, Alan Cox wrote:

> > Is this buffer inside the area X uses as display memory ? This  
> > would mean I have to set VID_TYPE_OVERLAY and VID_TYPE_FRAMERAM and  
> > the buffer would have some strange layout ( bytesperline as  
> > mentioned in your API draft is larger than the the number of bytes  
> > in one frames line ). Did I get you right ?!?
 
> The OVERLAY|FRAMERAM is meant for devices which DMA or otherwise write
> directly into image memory. Devices that overlay by chromakey are 
> not going to need it. Devices that work by copying the image at a fixed
> size and format into offscreen space arent really covered right now as
> we have no way to tell the Xserver 'give me a rectangle of video ram'.
I think I got it right now. In my case I do not care about VIDIOCSFBUF 
and capture my images to some place inside the framebuffer that is 
hopefully not used by X. 
It is really interesting to hear that v4l does not yet cover the case of 
a device that does not capture via DMA but write directly into its 
framebuffer and then overlays this image on the visible area. I always 
thought i missed some point :)

> Theres been some discussion of these issues with the XFree people and
> hopefully 4.0 will address a lot of this stuff.
Does anyone have a clue when that 4.0 will be available.

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List:       linux-video
Subject:    Re: [video4linux] Driver for ATI All-In-Wonder et al.
From:       Alan Cox < alan () cymru ! net>
Date:       1998-06-17 18:38:41

> It is really interesting to hear that v4l does not yet cover the case of 
> a device that does not capture via DMA but write directly into its 
> framebuffer and then overlays this image on the visible area. I always 
> thought i missed some point :)

Its not covered because we still have to work out with the X guys how
to cover it.

Alan
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