README.md: improve instructions for sunxi versions

If the user wants to build the sunxi version of the kernel they can specify
the PREFERRED_PROVIDER block in their conf/local.conf (i.e. they don't need to
edit the layer explicitly).

Also, now that gcc-5.2 is the default on master, inform the user how they can
continue to build the sunxi version (3.4%) version of the kernel by forcing
the compiler to version 4.9.

Signed-off-by: Trevor Woerner <twoerner@gmail.com>
This commit is contained in:
Trevor Woerner 2015-09-21 22:01:03 -04:00
parent 8a9c1d688c
commit d32866858f

View File

@ -21,8 +21,9 @@ Most Allwinner devices and hardware are supported in mainline kernel and 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
If you want to switch back to sunxi versions for some reasons (no device tree available, unsupported hardware), change the file
/conf/machine/include/sunxi.inc and set
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
- edit your conf/local.conf to add the following block
PREFERRED_PROVIDER_u-boot="u-boot-sunxi"
PREFERRED_PROVIDER_virtual/bootloader="u-boot-sunxi"
@ -33,6 +34,10 @@ If you already have built the mainline versions it might be necessary to reset t
bitbake -c clean linux
bitbake -c clean u-boot
Also, older kernel versions such as this don't build successfully with any gcc version 5.0 or newer. Since gcc-5.2 is the current
default compiler on master, if you wish to build this kernel with master you'll need to add the following to your conf/local.conf:
GCCVERSION = "4.9%"
Performance
===========