I'm sure there is a lot of people out there whose inner hackers wants to someday get involved with open source Radeon driver or Mesa development, but lack of introductory and scattered material makes it to look like a black box to them. So I'm asking developers involved with Mesa and open source drivers development to take a part in this discussion and share their experience.
We are going to assume that target audience (newbie) does already have a solid knowledge of C programming language.
1) First things first. What is usual set of documents, tool chain and software required to develop, test and debug drivers by developers?
2) Where to access source code, fork and start developing?
3) What compiler switches and libraries should be used during development?
4) How is work flow of development and testing drivers happening? (Dual boot, virtual machines, etc)
5) Is it mandatory to have access to multiple generations of hardware to get started?
6) How is Mesa and open source drivers source code structured? (Related directories and files)
7) How do drivers work internally? (Important functions and their calling order)
8) Where are the usual hot spots and how to profile the code?
9) What is usual coding conventions and styles being used?
10) What kind of tasks should newbies start with? Is there any list?
11) Who and where to ask when in trouble?
Feel free to add your own if anything necessary is missed.
The hardware documentation is here, but good knowledge of OpenGL and/or Direct3D is assumed if you want to understand the 3D docs:
http://cgit.freedesktop.org/mesa/mesa/ - OpenGL driver
http://cgit.freedesktop.org/xorg/driver/xf86-video-ati/ - X driver
http://cgit.freedesktop.org/mesa/drm/ - some shared code between the two above
http://cgit.freedesktop.org/~agd5f/linux/ - Alex's kernel tree with latest stuff for Radeon
http://llvm.org/docs/GettingStarted.html - The shader compiler backend for Southern Islands lives in LLVM, so you might need that too.
mesa/src/mesa/state_tracker - the OpenGL middle-end
mesa/src/gallium/drivers/radeonsi - the hardware driver (API-independent back-end)
And there is also a lot of code in various directories of Mesa that the 3 parts above use.
[email protected] can be a good start.
And OpenGL Super Bible, if you are serious: http://www.openglsuperbible.com/
Understanding GPUs from the ground up
And special thanks to you Marek for stepping forward and sharing with us!
1) If it's the kernel part of the driver, you need a complete reboot. The kernel mostly does low-level tasks like mode setting, memory management, and sending commands to the hardware. If you work on those, you'll reboot very often.
2) If it's the X driver, you need to restart X (just log out and log in)
3) If it's the Mesa OpenGL driver, you only need to restart the app that you test with, because the OpenGL driver is loaded when an OpenGL context is created. It's the same for VDPAU and OpenCL.
Ian Romanick posted a wiki with some project suggestions for people wanting to get into Mesa development. Hopefully, experienced people will avoid these projects.
The announcement: http://lists.freedesktop.org/archive...er/048905.html
That's a very useful page indeed; Objectives and required steps are all clear.