Hi.
Not sure if this affects anybody. Anyhow. I'll talk a bit about my
findings. This relates to my Cubitruck and an ARCH minimal
installation.
ARCH is using the mainline kernel nowadays. The one that Torvalds and
his gang manages. The aged - but complete - sunxi-kernel is no longer
used.
The script.bin file (kind of BIOS settings) under /boot known from the
sunxi-kernel used on the SOA image, is not being used on an ARCH minimal
install anymore.
Instead they use the so called kernel Device Tree and a so called device
tree blob (.dtb) inside u-boot. That .dtb replaces the script.bin file
known from sunxi-kernels.
Unfortunately this .dtb (related sources are stored in .dts) is
hardcoded and all but complete. It can not easily be edited like the
good old .fex files.
Those of you who try to build a minimal ARCH install + SOA on your own
have to watch out. E.g. WLAN, HDMI and more won't work on the mainline
device tree.
Basically you'd need the .dts files properly and complete prepared and
next you'd need the drivers (kernel modules). None of it is done
properly.
I think ARCH Linux as a base can not be used anymore!!! Being bleeding
edge comes at a high price, at least in the Cubitruck case.
Some words about the .dts source file
If you download u-boot ( the bootloader) sources you'll find the so
called Device Tree file under
./u-boot/arch/arm/dts/sun7i-a20-cubietruck.dts
you'll find fields inside that look like
Code:
--------------------
&ir0 {
pinctrl-names = "default";
pinctrl-0 = <&ir0_rx_pins_a>;
status = "okay";
};
--------------------
I worked with the script.bin in the past to turn on and off devices that
were not required.
The "status" field of a device inside the .dts tells you, if a device is
on or off. In above example it's the infrared device.
If you want to turn it off you need to change the status field.
Code:
--------------------
&ir0 {
pinctrl-names = "default";
pinctrl-0 = <&ir0_rx_pins_a>;
status = "disable";
};
--------------------
Then you have to recompile u-boot and to rewrite the u-boot image to the
sd-card.
It's a real challenge to keep track on all these changes for all these
boards and all these OSes and all these apps.
Cheers
::: ' Touch Toolbox and more' (http://soundcheck-audio.blogspot.com) :::
by soundcheck
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