ssvb / Xf86 Video Fbturbo

xf86-video-fbturbo - video driver, primarily optimized for the devices powered by the Allwinner SoC (A10, A13, A20). It can use some of the 2D/3D hardware acceleration features.

And because this driver is based on xf86-video-fbdev (with none of the original features stripped), it actually supports all the same hardware as xf86-video-fbdev. Essentially, xf86-video-fbturbo can be just used as a drop-in replacement and run on practically any Linux system. There will be no real difference on x86, but any ARM based system should see better performance thanks to some additional optimizations (the elimination of ShadowFB layer, ARM NEON/VFP code for dealing with uncached framebuffer reads, automatic backing store management for faster window moves).

== 2D graphics acceleration features ==

Hardware accelerated window moving/scrolling on Allwinner A10/A20 (using the G2D Mixer Processor).

Hardware accelerated window moving/scrolling on Raspberry Pi (using the BCM2835 DMA Controller)

== 3D graphics acceleration features ==

First a disclaimer to prevent any possible misunderstanding. The Xorg DDX drivers (neither this one, nor the others) do not do any actual 3D acceleration by themselves. They are nothing else but just a glue between the 3D drivers and the X11 window system. Still a poorly implemented glue can easily become the source of major performance problems. So it's important to do it right.

This DDX driver provides integration for Mali 400 GPU into Xorg. Any device with Mali 400 should have a properly working OpenGL ES 2.0 acceleration if it has Mali/UMP modules in the Linux kernel and libMali.so proprietary binary blob installed in the system. Additionally, the hardware overlay feature of Allwinner A10/A13/A20 display controller allows to support zero-copy OpenGL ES buffer flipping without tearing. The rest of the devices with Mali 400 hardware (Exynos4, Rockchip, ...) are expected to have roughly the same 3D performance as when using the reference vendor provided Xorg DDX driver xf86-video-mali.

== Video acceleration features ==

XV overlay is supported on Allwinner A10/A13/A20.

== Installation instructions ==

https://github.com/ssvb/xf86-video-fbturbo/wiki/Installation

== Troubleshooting ==

If something does not work right, it's a good idea to check dmesg log and /var/log/Xorg.0.log for any suspicious error messages or warnings. Some important notes:

1. The messages "(EE) FBTURBO(0): FBIOPUTCMAP: Invalid argument" in Xorg.0.log can be safely ignored. They are harmless.

2. If you are limited by exactly 60 FPS in benchmarks and want to see more, then just change option "SwapbuffersWait" to "false" in /etc/X11/xorg.conf Buffer swaps are synchronized to vertical refresh by default on Allwinner hardware. This is generally good for the applications, but bad for benchmarks.

3. If there is still a high CPU usage in Xorg server and the performance is poor for 3D graphics on Allwinner hardware, please make sure that the framebuffer size reservation is large enough to allocate memory for DRI2 buffers. The value fb0_framebuffer_num needs to be set at least to 3 in the fex file. Also if you have a compositing window manager, then compositing (the desktop effects) should be disabled for best performance.

   The expected final score for glmark2-es2 on Allwinner A10 hardware with "SwapbuffersWait" set to "false" is more than 100-150. Some of the individual tests from glmark2-es2 should run with more than 200-300 FPS.

== Contacts. Reporting bugs ==

If something from the list above does not seem to work right, then that's likely either some misconfiguration issue or a bug in the code. Don't hesitate to ping me on #linux-sunxi, #odroid or #gentoo-embedded channels at freenode.net irc. I'm known as "ssvb" there. The platforms other than allwinner/sunxi are also supported.

Or alternatively just use the issue tracker for reporting bugs: https://github.com/ssvb/xf86-video-fbturbo/issues

== Links to the other interesting projects ==

• http://limadriver.org
• https://github.com/jemk/libvdpau-sunxi

== TL;DR ==

This Xorg driver is a superset and drop-in replacement for xf86-video-fbdev and xf86-video-mali drivers. It just generally provides better performance on ARM hardware.