Gallium3D - Mesa's New Driver Model
13 likes4,662 views
Gallium3D is Mesa's new driver model that addresses issues with the classic model. It separates driver responsibilities into reusable components: a state tracker handles APIs like OpenGL, a pipe driver abstracts the hardware, and a pipe winsys interfaces with the operating system. This makes drivers more portable and easier to develop while supporting multiple graphics APIs on a single hardware driver.
Gallium3D - Mesa's New Driver Model
- 1. Gallium3D - Mesa’s New Driver Model Chia-I Wu olvaffe@gmail.com Mar 27, 2011 Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 1 / 24
- 2. Agenda Who Am I? main developer of Mesa EGL stack Android(-x86) port of Mesa experiences in OpenGL stacks Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 2 / 24
- 3. Agenda Who Am I? main developer of Mesa EGL stack Android(-x86) port of Mesa experiences in OpenGL stacks a member of 0xlab Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 2 / 24
- 4. Agenda Agenda OpenGL and Linux: DRI classic and Gallium3D driver models how does it make a developer happy Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 3 / 24
- 5. OpenGL and Linux Mesa v.s. Proprietary Drivers Isn’t this the case? Mesa Proprietary stability . v performance . v feature set . v it’s free v . Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 4 / 24
- 6. OpenGL and Linux Not Always Figure: nouveau v.s. nVidia binary driver (phronix) Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 5 / 24
- 7. OpenGL and Linux People BIG TEAMS / BIG BUDGET Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 6 / 24
- 8. OpenGL and Linux DRI Direct Rendering Infrastructure, DRI direct rendering Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 7 / 24
- 9. OpenGL and Linux DRI Direct Rendering Infrastructure, DRI direct rendering core X rendering indirect rendering Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 7 / 24
- 10. OpenGL and Linux DRI Components Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 8 / 24
- 11. OpenGL and Linux DRI Components <hw> dri.so is the DRI or 3D driver <hw> drv.so is the DDX or 2D driver <hw>.ko is the DRM kernel module libdrm <hw>.so is the user space library for the DRM module GLX and DRI2 are X11 protocols Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 8 / 24
- 12. OpenGL and Linux They are all complex DRM driver for buffer management, mode setting, ... (radeon has ∼70k LoC) DDX driver for 2D operations, video, mode setting, ... (radeon has ∼100k LoC) DRI driver for OpenGL (radeon has ∼90k LoC) Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 9 / 24
- 13. OpenGL and Linux OpenGL under Mesa Classic Driver Model libGL.so <hw>_dri.so libdrm_<hw>.so DRI driver interface Mesa common code HW code In the classic model, there is common code that checks the arguments of an OpenGL call and updates internal states it then calls into the HW code using the function table implemented there There is an almost one-to-one mapping between OpenGL API and the function table that the HW code implements. Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 10 / 24
- 14. OpenGL and Linux Dissection of the DRI driver libGL.so <hw>_dri.so libdrm_<hw>.so DRI driver interface Mesa common code HW code OS dependent: the HW code display server dependent: none OpenGL dependent: the common and HW code Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 11 / 24
- 15. OpenGL and Linux Problems with the Classic Model The problems with the classic model are it is OpenGL(ES) only; even the hardware can support OpenVG, OpenCL, ... the driver uses OpenGL data types and objects the driver must handle the differences between OpenGL and the hardware an implementation issue instead of a design issue in view of the DRI architecture Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 12 / 24
- 16. Gallium3D Ideal Model Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 13 / 24
- 17. Gallium3D Gallium3D libGL.so <hw>_dri.so libdrm_<hw>.so DRI state tracker pipe driver pipe winsys OpenGL state tracker OS dependent: the pipe winsys display server dependent: none OpenGL dependent: OpenGL state tracker Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 14 / 24
- 18. Gallium3D Gallium3D libGL.so <hw>_dri.so libdrm_<hw>.so DRI state tracker pipe driver pipe winsys OpenGL state tracker OS dependent: the pipe winsys display server dependent: none OpenGL dependent: OpenGL state tracker The pipe driver is highly protable and has a well-defined interface! Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 14 / 24
- 19. Gallium3D Classic Model to Gallium3D Model libGL.so <hw>_dri.so libdrm_<hw>.so DRI driver interface Mesa common code HW code DRI state tracker pipe driver pipe winsys OpenGL state tracker This is a non-trivial process DRI and OpenGL state trackers are written once and shared the pipe driver and winsys must be written for each HW new drivers should adopt the Gallium3D model from beginning Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 15 / 24
- 20. Gallium3D Gallium3D: examples libEGL.so egl_dri2.so <hw>_dri.so libdrm_<hw>.so DRI state tracker pipe driver pipe winsys OpenVG state tracker libOpenCL.so <hw>_dri.so libdrm_<hw>.so DRI state tracker pipe driver pipe winsys OpenCL state tracker (You can also have all OpenGL, OpenVG, and OpenCL state trackers inside a single DRI driver) Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 16 / 24
- 21. Gallium3D Gallium3D: even for DDX Xorg <hw>_drv.so (DDX) libdrm_<hw>.so DDX state tracker pipe driver pipe winsys A modern DDX driver is more than a 2D driver EXA/UXA Xrender video decoding mode setting KMS Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 17 / 24
- 22. Gallium3D Gallium3D: SVGA VMWare has a virtual GPU named SVGA. The aquisition of Tungsten Graphics gives vmwgfx.ko DRM module Gallium3D based DRI driver Gallium3D based DDX driver Gallium3D based D3D9 driver (D3D9 state tracker + Windows winsys) Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 18 / 24
- 23. Developers Gallium3D core Gallium3D core consists of two interfaces: struct pipe screen and struct pipe context helper functions for format conversions, buffer management, vertex processing, and etc. wrappers of OS or compiler dependent functions, such as threads, timing, I/O Pipe drivers implement struct pipe screen and struct pipe context interfaces. State trackers are users of the interfaces. Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 19 / 24
- 24. Developers struct pipe screen The pipe screen is an abstraction of the adapter. It is used for querying adapter capabilities/limitations creating resources fencing and other misc operations Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 20 / 24
- 25. Developers struct pipe context The pipe context is an abstraction of the graphics pipeline (and some misc operations) vertex buffers vertex fetcher vertex shader geometry shader stream output buffers textures and constant buffers rasterizer fragment shader per-fragment ops color and depth buffers Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 21 / 24
- 26. Developers Pseudo Code /∗ c r e a t e t h e p i p e s c r e e n ∗/ s t r u c t p i p e s c r e e n ∗ s c r e e n = o p e n h w d e v i c e ( dev name ) ; /∗ c r e a t e a p i p e c o n t e x t ∗/ s t r u c t p i p e s c r e e n ∗ p i p e = s c r e e n −>c o n t e x t c r e a t e ( / ∗ . . . ∗ / ) ; struct pipe resource ∗ res ; /∗ c r e a t e a r e s o u r c e from t h e s c r e e n ∗/ r e s = s c r e e n −>r e s o u r c e c r e a t e ( / ∗ . . . ∗ / ) ; /∗ s e t t h e r e s o u r c e a s t h e f r a m e b u f f e r ∗/ p i p e −>s e t f r a m e b u f f e r s t a t e ( / ∗ . . . ∗ / ) ; Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 22 / 24
- 27. Developers It is easier Gallium3D driver model has well-defined interfaces and types is close to the hardware has reusable state trackers has lots of helper functions supports pipe screen/context wrapping: trace, rbug, galahad Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 23 / 24
- 28. Q&A Q&A Questions? Chia-I Wu (olvaffe@gmail.com) Gallium3D - Mesa’s New Driver Model Mar 27, 2011 24 / 24