README.md: document how to select gfx drivers

Update documentation to clarify how to select the use of mainline graphics
drivers lima and panfrost.

Signed-off-by: Diego Rondini <diego.rondini@kynetics.com>
This commit is contained in:
Diego Rondini 2020-03-18 22:45:30 +01:00
parent 1d6ef084db
commit 74a488e2ef

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@ -19,8 +19,12 @@ Maintainers:
Kernel / U-Boot Version
===========
Most Allwinner devices and hardware are supported in mainline kernel and U-Boot, so this layer builds mainline by default.
Legacy sunxi Kernel / U-Boot
-----------
There is a custom U-Boot and Kernel version for sunxi devices which includes some special drivers not mainlined.
These versions are rather old (3.4 for kernel and 2014.04 for U-Boot), but may support more functions and devices than current mainline
These versions are rather old (3.4 for kernel and 2014.04 for U-Boot), but may support more functions and devices than current mainline.
If you want to switch back to sunxi versions for some reasons (no device tree available, unsupported hardware), either:
- change the file conf/machine/include/sunxi.inc to include the following block
@ -35,9 +39,16 @@ If you already have built the mainline versions it might be necessary to reset t
bitbake -c clean virtual/kernel virtual/bootloader
For mainline kernel we have now support for latest LTS, stable and bleeding edge (latest possible rc).
Mainline Kernel / U-Boot
-----------
For mainline kernel we have now support for latest LTS and stable.
By default we use latest LTS. If you would like to change version please update ```PREFERRED_VERSION_linux-mainline``` in:
* [conf/machine/include/sunxi.inc](https://github.com/linux-sunxi/meta-sunxi/blob/4921234ed77f9df77c65c88637ce50468f65bde7/conf/machine/include/sunxi.inc#L16)
* [conf/machine/include/sunxi.inc](https://github.com/linux-sunxi/meta-sunxi/blob/fa0846c0eb23e3424b89acb4d5a327e921f73497/conf/machine/include/sunxi.inc#L16)
When using mainline kernel ≥ 5.2 it is now possible to use the mainline graphics drivers *lima* and *panfrost*, instead of the *mali* driver provided by ARM. To enable open source mainline graphics support add the following line in your `local.conf`:
MACHINEOVERRIDES .= ":use-mailine-graphics"
Performance
===========