rm
Posts: 11
Joined: Mon Sep 12, 2011 12:25 pm

Re: X.org driver and GPU in general

Wed Jan 18, 2012 4:35 am

In the Xorg.0.log http://pastebin.com/xpj2mYpw the guy posted at http://www.reddit.com/r/raspbe.....board_ama/

the video device is shown to be using the FBDEV driver.

So I am wondering, is there a native X.org 2D driver for the GPU, and if so, how it is called? And is it free software, or proprietary?

Another question: in the log the GPU reports to have 4 MB of video RAM. Does that amount come from a part of the main RAM, and if so, is it configurable how much does it take, or is there simply 4 MB of dedicated video RAM on the chip?

User avatar
Chromatix
Posts: 430
Joined: Mon Jan 02, 2012 7:00 pm
Location: Helsinki

Re: X.org driver and GPU in general

Thu Jan 19, 2012 7:00 am

I've been told that the CPU and GPU share the available RAM, although it's not entirely clear how dynamic this might be - there are rumours of a fixed 64MB allocation to the GPU, which would be quite a large fraction (especially on the Model A).  I've also been told that Xorg is unaccelerated and using the bare framebuffer.

The easiest route to accelerating Xorg might be to map it onto OpenVG, which the GPU does accelerate.  It remains to be seen whether this is really necessary though.
The key to knowledge is not to rely on people to teach you it.

User avatar
Davespice
Forum Moderator
Forum Moderator
Posts: 1662
Joined: Fri Oct 14, 2011 8:06 pm
Location: The Netherlands
Contact: Twitter

Re: X.org driver and GPU in general

Thu Jan 19, 2012 5:03 pm

I've just been reading about the X windows system on Wikipedia.  I do remember an early video of Eben saying that they were missing accelerated X drivers.

This one, skip forward to 07:05.  He goes on to say that they're working with the Fedora / Redhat community to develop these X drivers - but that he was uncertain that they would be ready in time for release.

I wonder if Eben or Liz could give us an update on that?

Themroc
Posts: 44
Joined: Fri Jan 06, 2012 9:35 am

Re: X.org driver and GPU in general

Thu Jan 19, 2012 9:18 pm

Chromatix said:


The easiest route to accelerating Xorg might be to map it onto OpenVG, which the GPU does accelerate.


Any IEEE subscribers or members here?

http://ieeexplore.ieee.org/xpl.....er=5012187

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 23059
Joined: Sat Jul 30, 2011 7:41 pm

Re: X.org driver and GPU in general

Thu Jan 19, 2012 9:31 pm

Chromatix said:



The easiest route to accelerating Xorg might be to map it onto OpenVG, which the GPU does accelerate.  It remains to be seen whether this is really necessary though.


I've been looking for something like this - found a few projects with that as the intention, but nothing really solid. If anyone has any ideas or pointers to projects that do this, post them here!
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
"My grief counseller just died, luckily, he was so good, I didn't care."

User avatar
Davespice
Forum Moderator
Forum Moderator
Posts: 1662
Joined: Fri Oct 14, 2011 8:06 pm
Location: The Netherlands
Contact: Twitter

Re: X.org driver and GPU in general

Fri Jan 20, 2012 11:29 am

I've done a bit of asking around on Freenode and a couple of people mentioned the Intel Glamour project.  But I am not sure if that is helpful or relevant.  I'm also trying to find someone who can access the IEEE article for us.

rjw57
Posts: 33
Joined: Wed Sep 07, 2011 1:21 pm
Contact: Website

Re: X.org driver and GPU in general

Fri Jan 20, 2012 12:07 pm

I've a copy. Unless you're a member of the same institution as I (University of Cambridge), I probably can't send you it. I've read it however.

It is relatively unenlightening and is only 2 pages long. In essence, they took the freedesktop.org server (X.org) and implemented a EGL/OpenVG based graphics driver. They don't state how they get input events but I imagine it's the usual Linux input event layer.

I suspect the best thing to do is to email the authors and ask for any code they may have.

User avatar
Davespice
Forum Moderator
Forum Moderator
Posts: 1662
Joined: Fri Oct 14, 2011 8:06 pm
Location: The Netherlands
Contact: Twitter

Re: X.org driver and GPU in general

Fri Jan 20, 2012 12:12 pm

Hi rjw57.  Does the document have their email addresses?  If so could you PM them to me and I'll get in touch to ask them.

rjw57
Posts: 33
Joined: Wed Sep 07, 2011 1:21 pm
Contact: Website

Re: X.org driver and GPU in general

Fri Jan 20, 2012 12:19 pm

No, but Google suggests that the first author may be contacted at dongkyun.jeong -at- samsung.com. All authors appear to work for various sub-divisions within Samsung.

User avatar
Davespice
Forum Moderator
Forum Moderator
Posts: 1662
Joined: Fri Oct 14, 2011 8:06 pm
Location: The Netherlands
Contact: Twitter

Re: X.org driver and GPU in general

Fri Jan 20, 2012 3:54 pm

Okay, I have emailed him asking if we can look at the source code from the PXA320 mobile with F3D2000 GPU implementation mentioned in the article.

User avatar
MattPurland
Posts: 57
Joined: Fri Apr 13, 2012 7:37 pm

Re: X.org driver and GPU in general

Wed May 09, 2012 5:34 pm

Sorry to bring back an old post, but was there any progression with this? Getting an accelerated desktop would be pretty handy! (running at 1080p on the framebuffer is nasty to say the least...)

UnaClocker
Posts: 12
Joined: Sat May 12, 2012 5:48 pm
Contact: Website

Re: X.org driver and GPU in general

Mon May 28, 2012 12:25 am

Still hoping for progress on this. Eventually the right person is going to come along with the skills to write this driver. I would think that since Broadcom opened the datasheet for this CPU, the relevant info should be out in the public now.

User avatar
teh_orph
Posts: 346
Joined: Mon Jan 30, 2012 2:09 pm
Location: London
Contact: Website

Re: X.org driver and GPU in general

Mon May 28, 2012 8:11 am

Not to toot my own trumpet here but progress is certainly being made: http://www.raspberrypi.org/phpBB3/viewt ... =63&t=4649
Also other people are working privately on this problem, behind the scenes.

Return to “General discussion”