1. In that Android image, device tree overlay files are copied into the 
/system/vendor/firmware directory of the root file system.

2. To disable HDMI, you must disable both the HDMI (video and audio) and 
HDMIN (video only) capes:

capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN

3. The overlay fragments of the "default" capes (LCD3/4/7, HDMI, eMMC, 
etc.) are compiled into the kernel itself.  They do not need to be copied 
into /system/vendor/firmware.  Only your own custom .dtbo files need to be 
copied into the firmware diretory.  If the LCD7 cape is plugged into the 
BBB at boot, it will be detected via the capebus manager in the kernel and 
the LCD7 cape's overlay will be automatically enabled.  The only thing that 
you will need to do to use the LCD7 cape is to remove the "video=" option 
from the kernel command line arguments in the uEnv.txt file and have the 
LCD7 cape plugged in at boot.  The resolution will be pulled automatically 
from the cape overlay, so you don't specify it on the kernel command line.

Cape overlays have a priority to their loading order on the cape bus.  In 
your case, the LCD capes have a higher priority than that of the HDMI.  If 
you plug in the LCD7 cape and turn the BBB on, the LCD7 cape gets control 
of the LCDC pins.  The HDMI and HDMIN capes will then fail to load because 
they both request the use of the LCDC pins, so HDMI is disabled 
automatically when the LCD7 cape is in use.

Echo-ing the name of a device tree overlay into the bone_capemgr does work 
for loading overlays, but only for custom .dtbo files that you copy into 
/system/vendor/firmware (rather than /lib/firmware under Linux).   

Andrew

On Monday, April 21, 2014 7:06:22 PM UTC-4, Samer Shatta wrote:
>
> Hi
> i am using android 3.8 (andrew henderson build)
> i have some questions on how to act with device tree over it :
>
> 1- where to find the available device trees ?
> in angstrom the .dts & .dtbo files are exist in /lib/firmware
> but in android i didn't find any folder that contain the dts or dtbo files 
> , so where can i find them ?
>
> 2- how to disable hdmi ?
> i try to append the following line to uENV.txt
>
> capemgr.disable_partno=BB-BONELT-HDMI
>
> but it dosen't work .
>
> 3- i want to enable lcd 7 cape manually how can i do that ?
> in angstrom i do that by the following echo command :
>
> echo BB-BONE-LCD7-01 > /sys/devices/bone_capemgr.8/slots
>
> but in android it also doesn't work .
>
> please help .
>
> Thanks
>

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