intel linux graphics

Intel Linux Graphics Following the open source road from

Kernel to UI toolkits

Eugeni Dodonov

LinuxCon Brazil 2011 2

Intel Linux Graphics

Let‟s start with 3 simple questions:

• How many of you run Linux on your notebooks and desktops?

• How many of you run Linux on your notebooks and desktops and

have integrated Intel graphics cards?

• How many of you run Linux on your notebooks and desktops, have

integrated Intel graphics cards, and ever had to download or install

some sort of drivers for them to work?

• Why?

• Let‟s figure it out…


What is Intel Linux Graphics?

A stack of graphics projects to support Intel Graphics cards

Composed of a range of projects from Kernel to end user facing UI

toolkits and applications:

• Kernel

• DRM

• Mesa 3D

• VAAPI

• Cairo

• DDX

• Wayland

• Fully open-source

• Fully upstream


What Intel Linux Graphics is not?

PowerVR-based cards

• GMA500, GMA600, or Poulsbo

• Those are closed-source

So, how does this all work?

5


So, how does this all work?

Let‟s start with the basics.

• At the very bottom, we have the GPU.

• To make things more interesting, we have different generations of

GPUs.

• Gen2, Gen3, Gen4, Gen5, Gen6, Gen7

• What are they?


A long, long time ago, in a galaxy far away…

First generation of Intel graphics:

• i740

• i810

• Museum


2nd generation, or Gen2

• i830, 845, 85x, 865

• Around a decade ago

• Support DirectX* 8.0 and OpenGL* 1.3 in hardware

• Support some video decoding

• But no hardware transform-and-lighting…


3rd generation, or modern days

• i915g, i915gm, 945g, 945gm, g33 and pineview

• More video processing, support for hardware video overlaying

• Support for DirectX* 9.0c, OpenGL* 1.4

• Supports Pixel Shader 2.0 in hardware

• But still no hardware transform and lighting…


4th generation, not so distant past

• Available somewhere around Intel® Core™ architecture

• i965g, i965gm, g45, gm45, g35

• Now yes, hardware transform and lighting support!

• Unified Shader Processor, support for Pixel Shader 3.0 and (later) Shader

4.0

• Still around us, but the real fun starts next…


5th generation, Intel® Core™ I architecture

• No more North Bridge, with the PCH design graphics support is

integrated into CPU.

• Ironlake family of chipsets.

• You can use most almost-modern graphics applications and play most

games.

• You can play OpenArena, Urban Terror*, and World of Padman with 30+

FPS (according to Phoronix benchmarks)

• Support mpeg and h264 decoding by hardware


6th generation, present day

• Intel Sandy Bridge architecture

• 70+ FPS in OpenArena in 1600x900 resolution, according to Phoronix

benchmarks

• In hardware, support for a whole new set of enhancements.

• Almost doubles graphics performance for integrated graphics

(+70% faster according to Anandtech benchmarks).

• Most modern Intel® Graphics chip out there.


7th generation, the future

• You all know that there will be new Intel architecture out there in a

couple of months.

• You all know that it will be called “Ivy Bridge”.

• …but that‟s about all I can tell you about it.

• Besides the fact that it is great .


Trivia 1

Do you know that you can discover a lot about your gfx card generation

and features from your kernel?

• cat /sys/kernel/debug/dri/0/i915_capabilities


Trivia 2

Use the Source, Luke!

• You can find out a lot about your graphics card by looking at the

sources.

• In kernel/drivers/gpu/drm/i915/i915_drv.c you can find a

precise mapping of different cards to their generations and other

details.

• Which brings us to our next topic…

Who are the members

of the Intel Linux Graphics family?

16


The Kernel

So, we have the GPU, but how to use it?

• The Kernel is the root of everything on a Linux system.

• Thanks, Linus!

• For Intel Linux Graphics, we have many places in the Kernel

• The most important are:

• Drivers/char/agp/intel-*.[ch]

• Chipset-specific support

• Drivers/gpu/drm

• DRM code

• Drivers/gpu/drm/i915

• i915.ko kernel driver. This is what talks to the hardware.


The Kernel, part 2

What does the kernel do?

• Does the mode setting (KMS, or Kernel Mode Setting) – resolutions,

refresh rate, different outputs and settings…

• GPU memory management

• Passing rendering instructions to the GPU

• Gives a /dev/dri/ interface for userspace applications to talk to

different GPUs in an unified way

• Power management

• And all the other low-level stuff


Trivia 3

Did you know that Intel Graphics cards have several power and

performance-related options?

• RC6 – deep sleep state. Allows the card not to use any power when

idle. Up to 60% battery improvements, according to Phoronix testing.

• i915.i915_enable_rc6=1

• FBC, Frame Buffer Compression. Allows the card to compress pixel

data prior to sending it to the GPU, using less memory bandwidth.

• i915.i915_enable_fbc=1

• Semaphores in hardware. Allows for a faster GPU scheduling.

• i915.semaphores=1

• Some are already ON by default, some hopefully will be by the Kernel

3.2 release.


But how do you talk to the Kernel?

DRM, Direct Rendering Manager.

• A component of Direct Rendering Infrastructure, which allows

applications to talk to the GPU directly.

• Used for video acceleration, rendering, 3D…

• Allows access to different GPU hardware (Intel, Radeon, Nouveau,

…) using a common /dev/dri interface.

• Userspace support using the libdrm project.

• http://cgit.freedesktop.org/mesa/drm/

http://cgit.freedesktop.org/mesa/drm/


Trivia 4

Did you know that Intel has a set of tools and utilities for managing,

monitoring, and having detailed control over the hardware?

http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/

• Intel_gpu_top, test_display, intel_reg_dumper, intel_error_decode,

intel_gpu_time…

Besides intel-gpu-tools, libdrm also has some nice utilities, which are

usually not that widely known.

• Modetest – tests different video modes and outputs

• Kmstest – tests Kernel mode setting

• And many others








Trivia 4 - examples

Intel_gpu_top

Intel_reg_dumper


What comes on top of libdrm?

So, we have DRM, but what uses it?

• Mesa 3D

• DDX

• VAAPI

• Cairo backends

• Wayland

• …and so on

• What are all of those?


Mesa 3D

Open-source implementation of OpenGL API.

Developed since 1993 by thousands of contributors.

Supports OpenGL 2.1, heading towards OpenGL 3.0 completeness by

the end of the year.

Supports most GPUs out there. And when it doesn‟t, it has software

rendering.

Fully open-source. Doubtless, the best source of information for those

wanting to understand how OpenGL works.

Has huge regressions testing suite (piglit).


Mesa 3D


Trivia 5

It is possible to record all the GL operations from Mesa, and use them for

analysis later using the APITRACE (https://github.com/apitrace/apitrace)

tool.

Or even replay the entire execution!

https://github.com/apitrace/apitrace

https://github.com/apitrace/apitrace


And what about 2D?

DDX, or Device Dependent X, or xf86-video-intel.

• 2D driver of the X server for Intel cards.

• This is what you use when you run X.

• http://cgit.freedesktop.org/xorg/driver/xf86-video-intel

http://cgit.freedesktop.org/xorg/driver/xf86-video-intel






Trivia 6

Currently, the officially support Acceleration mode for the 2D rendering is

UXA, developed back in 2008.

Earlier this year, Chris Wilson from Intel proposed and implemented a

new backend, called SNA (Sandy Bridge New Acceleration, or

Snazzy).

Improves Cairo performance by up to 15x in some cases, and 3D games

performance by up to 40-60% (depending on the game).

Most of the improvements come from optimized batch buffer processing,

so 2D operations are carried out together with 3D ones. Previously,

those were split and serialized between different rendering rings.

Not yet fully stable, but can be used through the --enable-sna compile

switch.


Video Acceleration from Intel

VAAPI – Video Acceleration API

• Provides access to GPU hardware for hw-accelerated video processing

(encoding, decoding, subpicture blending, and rendering).

• Supports mpeg-2, H.263, H.264, VC-1

(depending on the generation of video chips).

• Supports accelerating motion compensation, iDCT, intra-frame prediction,

variable-length decoding, bitstream processing, ….

• http://www.freedesktop.org/wiki/Software/vaapi

http://www.freedesktop.org/wiki/Software/vaapi


Cairo

(No, not the City)

• Library for vector graphics-based and device-independent API.

• A library for 2D drawings over a multitude of backends (xlib, xlib-xrender,

xcb, gl, glx, egl, glesv2; png, pdf, ps...)

• Used by many open-source projects: gtk, firefox, webkit, poppler, and so on.

• http://cairographics.org

http://cairographics.org/


Trivia 7

For performance analysis, it is possible to record all the Cairo operations

during execution, and analyze them later using the cairo-perf-trace

utility.

And it is also possible to compare different Cairo backends (x11, egl,

drm, and many others) to see which works better for each case.

Chris Wilson maintains a repository of interesting Cairo traces at

http://cgit.freedesktop.org/cairo-traces/






Wayland

A hot topic in today‟s Linux graphics world

But what is Wayland?

• New display-server protocol to allow compositing window managers to

communicate between applications and video hardware.

• It is not a reinvention of X11.

• It is not X12.

• It is not a magic silver bullet which will automagically fix all the X11 issues

and problems and provide the answer to life, the universe, and everything.

• (This would be 42, by the way)

• It is Wayland.


Wayland’s background

Started by Kristian Høgsberg (krh) as a free-time project.

Why?

• X Window System protocol and architecture came from 1980s, and most of

their aspects are not relevant anymore.

• However, we just cannot drop X due to the number of applications and users

out there.

• So, X won‟t go away that soon. Really, it won‟t.

But….


What is the idea of Wayland?

It is an attempt at getting the best ideas to allow applications to talk to

GPU by the means of compositing server.

- And keep it simple!


Wayland: how does it work?

Wayland is a protocol for communication between applications and a

compositing manager.

How does it work?

• A compositor runs on top of KMS and EVDEV.

• Applications talk to the compositor using the Wayland protocol.

• Compositor provides a rendering context to the applications (a window).

• Applications do whatever they want with this context, and notify the

compositor when their window contents are updated (or damaged).

• Compositor draws and „composes‟ windows on screen.

• Compositor checks the „scene graph‟ do detect which window should

receive the user input.

• That’s it.


Wayland: why?

So, why Wayland instead of extending X server?

• X protocol is big.

• X architecture is complex.

• Wayland is tiny.

• Wayland is simple.

• They can co-exist!

• Wayland compositors can run X applications.

• Wayland compositors can run on top of X.


Trivia 8

It is possible to mix Wayland applications which run from X Window

System with the ones running from the console.

38

Wrapping up…


So, what are the conclusions?

What is Intel Linux Graphics?

• A stack of open-source graphics projects

• Covers an entire range from the hardware to user-facing applications,

passing through Kernel and middleware libraries

• Fully upstream

• Fully open source

http://www.intellinuxgraphics.org/

• Developed by:

• Intel

• With the help of Redhat, Canonical, Suse, …

• And YOU (the community!)

• How can I contribute or help?



Contributing

Writing bug reports?

• Yes, there are bugs.

• Yes, there are different bugs.

• And yes, there are bugs which we are not aware of. And we won‟t be aware

of until you tell us!

• http://intellinuxgraphics.org/how_to_report_bug.html

http://intellinuxgraphics.org/how_to_report_bug.html

http://intellinuxgraphics.org/how_to_report_bug.html


Contributing 2

Coding and sending patches.

• It is all open source!

• Some Intel employees started this way (Daniel Vetter).

• You can help on a range of projects!

• Kernel patches

• MESA GL extensions

• Cairo patches

• Wayland development – contributors are welcome!


Contributing 3

Testing

• We have a great QA team.

• We have a huge community.

• We have amazing developers.

• But we don‟t have all the combinations of hardware, distributions, versions,

and their variations.

• If you have an issue, let us know!

• This is how open source community works.


Contributing 4

Use your creativity!

After all, the source is out there!


Want to learn more?

Main site: http://www.intellinuxgraphics.org/

Many developers post to the Planet Freedesktop at:

http://planet.freedesktop.org/

I have a blog where I semi-periodically cover everything that happens

within the Intel Linux Graphics land and community at:

http://dodonov.net/blog/category/intel/.

Some exciting news is on the horizon for Intel Linux Graphics.

Stay tuned!


http://planet.freedesktop.org/

http://dodonov.net/blog/category/intel/


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