Standards, agreenments and fragmentation

The graphics area can be seen through your OpenSource "standards" and industry _standards_. Even when discussion only about Linux and not even going to the Microsoft land the field is starting to be a quite messy.

The fragmentation in open source side is in many areas caused by the fact that the communities are competing with each other. They want to ensure that they can bring out as good as possible SW as soon as possibly - naturally. What this causes is that instead of making an effort and developing something together we fragment. Good examples of this is your TTM vs. GEM, classic Mesa vs. Mesa Gallium state tracker or EXA/XAA/UXA.

Then we have our industry standards by Khronos. What Khronos defines is an open standard mainly for Graphics and Media. We have the defacto OpenGL/ES and the counterparts GLX and EGL and then we have something else. We have things like OpenWF (display and Composition) which in OSS world is know as KMS (with limited composition support), OpenKODE with the OSS counterpart being SDL and OpenMAX which in OSS world is tackled with VAAPI or XvMC or VDPAU. Well you get the point.

So why should we care about this? What this all means is that the set of selection when developing an Linux based system - following the industry standards or selection one of the Open Source paths. Often the proprietary drivers do follow the industry standards but they have not adopted any of the OSS ways of providing the functionality and why would they as the OSS "standards" are often vendor specific. This will mean that reasonable way to build our platform would be the industry standards but then you would loose the possibility to try out the new nice things which are not executable in these platforms. Difficult choice and ideally a choice that we wouldn't need to do.

UI done right

I have always been a fan of what the guys at TAT are doing. These guys have really understood the whole thing of making great looking UI's in away that it is respecting the underlaying HW and taking every last bit out of it.

Their latest creation Velvet is just that - innovative, simple, great looking UI. Nice job!


PS. Would be nice to understand how these guys are working. You have your UI designer, framework developer and lower level graphics guy all working seamlessly together...

New Gnome-Shell release ... reminds me of something

Gnome-Shell had an new release published at mid last month. The new release is now dependent from GTK3.0 and at least according to different sources should be more stable and performing - ready for a test drive.

So what is this Gnome-Shell.
Well Gnome-Shell is your integrated window manager, compositor, and application launcher. It uses Clutter canvas as an scene where your GtkWindows are reparented as actors. The main logic behind this is under Mutter, an fork from Metacity.

The architecture is done in such away that the window manager, compositor, and application launcher are tightly coupled together. With this approach there is no need to provide any additional abstraction layers to different WM/CMs or any scene/graph abstraction. Also with this the GNOME guys have the full control of the stack. Because of the architecture Gnome-Shell has been receiving quite a bit of comments especially from the Compiz people. This as the approach will make other WM/CMs live quite difficult.

With the architecture, it is actually funny how it reminds the Hildon 5 architecture - composition with clutter canvas as scene, Hildon desktop integrated appl launcher, desktop integrated Window Manager, etc. and everything nicely coupled together.


As from the user experience,
launching the latest and greatest Gnome-Shell with my Intel 855GM based based device was an extremely slow experience. Gnome-Shell was really unusable. Bit of an Googling revealed that syncing to VBlank might be the root cause for this problem as it is enabled by default. "export CLUTTER_VBLANK=none" seemed to be the cure for this problem. Wonder why this problem... (bit of a debugging might be in place). This trick makes it at least testable.
The main thing that I noted with the Gnome-Shell is that you really want to learn to use the basics - your ALT+F2 key combo. The new Application Area did not at least convince me. Maybe as the usage is going towards more basics it would be time to put the good old Awesome back in use - going really back to basics...

When accleration came to browser

HW accelerating in website rendering has become an hot topic along the HTML5. Mozillas answer to this demand is their new Layers architecture.
Mozilla's Layers allows browser to take the suitable parts of the rendering to GPU and of course along that to get some eye candy to the end users. Idea is to divide the logically different parts of the rendered content to different layers allowing better division between the CPU and GPU.

The Layers will structure a layer tree which constructs the final webpage. To simplify, they have a container (representing the surface) and its leafs (including the actual graphical data). The final render is constructed from the textures generated from the leafs and composited to the screen.


The basic layer infra will include ThebesLayers, ContainerLayers and a LayerManager.

The Manager is responsible of constructing the layer tree and rendering that to the destination context. The rendering is always happening as an result of an transaction to the tree and only happening to the visible region parts of the texture.

The Container layers task is to group together the child layers beneath it. It represents the surface into which its children are composited and handles the Z order of the its children.

Thebes in general is nothing new. It has been part of the Mozilla gfx architecture already quite awhile as an C++ wrapper for Cairo API's and as an API for text handling.
The ThebesLayer abstracts the Thebes surface which is used to display items that will be rendered (surprise, surpise) using Thebes. So Cairo Image surface drawn to by Cairo. The question is of course - why not doing this directly with Cairo? Why the wrapper? - Some discussions about this from Bas's blog comments.

There is bit of an older bug in Mozilla bugzilla explaining this basic functionality in detailed. In principle what you get with the basic functionality is what you already have - Cairo content shown to the screen. Of course besides the basic functionality you will also need some additional layers for video, something for webgl plus you would also like to have optimized way of doing the rendering. So not all about just basics.


What from my point of view makes this layers especially in interesting are the plans to bring layers to also to Fennec 2.0 along the other goodies like Electrolysis. It will be most definitely interesting to see how it performs and behaves in a more limited environment.

BTW the first bits of layers are already available through the latest nightly builds of Firefox4. The usage of the layers is still limited to Windows/GL, full-screen video only but the sources are available for seeing and testing.

Difficulty of developing Open Source Linux drivers for GPU

During the last few days there as been an active discussion ongoing at dri-devel list about Open Source Graphics drivers. The discussion was initiated by Qualcomm's RFC message - [RFC] Qualcomm 2D/3D graphics driver.

Qualcomm's Linux team has been working on Open Sourced Kernel drivers for their chipset. What they have done so far is that they have build DRM driver with a limited set of supported functionality to enable DRI2. Their own userland parts of the drivers do still utilize the KGSL (Kernel Graphics Support Layer) interface to allocate memory making DRM just as an API to be more closer with the mainstream Linux Graphics stack. Qualcomm does still have some plans in the future to move to an standard design - possibly TTM.


The dri-devel list the opinions about drivers with an userland binary blobs was made quite clear - if you aren't going to open the whole drivers don't try to push them to mainline. Basically the door was slammed from the Qualcomm efforts for pushing the drivers in.

In between the lines I think there were some excellent point made in this discussion.
The bottom line is that the community cannot work with the drivers if there exists and dependency to closed sourced userland - this is definitely clear. With this kind of an setup it is just impossible to work with the drivers. On the otherhand if the community is going to bombard down all the drivers with the closed userland parts (even without making sure what are the attemts to open source them) how are we ever going to see open sourced mobile GPU drivers? From my point of view the community also has the means to guide this work to right direction - giving comments to the request. It really seems that the Qualcomm guys do have the enthusiasm to develop the open source drivers. How about making sure that these guys are taking the correct steps also with the userland and making sure that the Kernel bits are as they should?

MeeGo for handsets getting its UI

MeeGo for handsets has taken its next step and is now capable to provide MeeGo User Experience also for mobile users - see the blog entry.
There is some nice screenshots and video showing its functionality. Unfortunately the downloadable image is only available for Moorestown based Aava device. The N900 image still needs to be compiled by hand - instructions from here and repo from here.

GLES1.1/2.0 on Mesa DRI and a bit about Gallium

Mesa has had GLES 1.1/2.0 already since since last year through Gallium state trackers. What this means is that Gallium based drivers are capable of providing support GLES support for end users. Now there is also an activity ongoing to get the Mesa GLES1/2 support to work with DRI drivers and along that to expose multiple GL APIs without separate state trackers on Gallium side.

This work on GLES 1.1/2.0 on DRI made by Kristian received good feedback also Gallium driver developer and is now merged to Mesa.


The discussion about classic Mesa vs. Mesa Gallium State Tracker in general has not lately been this productive (see the Mesa thread). Intel guys are clearly wanting to stay with the classic drivers, and whom could actually blame after all the work that Intel has place to get their drivers to perform. Currently Nouveau camp is the only one that is really utilising Gallium3D and the RedHat guys are going to ship the latest free software NVIDIA bits with the upcoming Fedora 13.