[Gta04-owner] xf86-video-omap

Neil Jerram neil at ossau.homelinux.net
Fri Oct 21 14:44:18 CEST 2011


On Fri, 21 Oct 2011 14:14:52 +0200, Dr. H. Nikolaus Schaller wrote:
> Hi Neil,

Hi, thanks for the quick reply.


> I have not looked into details but I think all the drivers are 
> completely
> open source and free.

Just to be clear: I wasn't questioning whether the _currently_ used 
drivers are free; my doubt was only about the newer "xf86-video-omap" 
driver, which GTA04 isn't using now.

> On the kernel level there was a 'DSS' driver which was replaced
> by a new DSS2 driver. That one allows to control the OMAP
> display hardware controllers so that they DMA from memory
> through an overlay manager to either LCD and/or TV out.
>
> I think the DSS2 is also capable for rotation (it would just
> address the framebuffer memory differently) but some bits and
> pieces may be missing in the 2.6.32 kernel.

Yes.  I found 
http://www.mjmwired.net/kernel/Documentation/arm/OMAP/DSS.

It looks like rotation might be as simple as adding omapfb.rotate=3 to 
the boot command line.

Do you know if it's generally safe to play with this kind of thing?  Or 
do I risk frying my components?

> About the references you have found I think they are yet
> another video driver. I am not sure if it will replace DSS2
> but some hints are that it is about dynamic memory allocation
> in the kernel and zero-effort rotation.

And 2D acceleration, I believe.

But anyway; after seeing xrandr not work, I had jumped a bit too 
quickly to the conclusion that a different video driver (i.e. omap 
instead of omapfb) would be better.  But thanks to your reply I can now 
see that it will probably be quite easy to get rotation with the 
existing driver.  It just needs a little experimentation.

       Neil



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