Remove item from slots


Is there a way where we can remove items from slots (/sys/devices/bone_capemgr.9/slots)? I know how to get something into the slot for device tree overlay, but how do I remove it. I want to remove Bone-LT-eMMc-2G particularly off slot 4.



Yes - you can unload it. I believe the proper syntax is something like:
echo -4 > /sys/devices/bone_capemgr.9/slots

Hi Kurt,

I tried and I wasn’t able to remove it.

For a normal overlay, just reboot. You are supposed to be able to
write a negative number into slots to remove overlays, but right now
that's a good way to crash your kernel.

If you want to remove the "virtual" eMMC or HDMI capes on a 'Black,
however, you will not be able to (even if removing it didn't cause
erratic behavior). Instead you have to avoid loading the capes in the
first place by passing a parameter to the kernel. In most uboot
setups, you can do this by setting the optargs= variable in your
uEnv.txt file:


The above line will disable both the HDMI and the eMMC drivers,
allowing you to use all the I/O pins on the 'Black.

Make sure when editing that you are changing the *CORRECT* uEnv.txt
file! Some distributions have more than one copy (typically one in
/boot and one in /uboot). You need to make sure the one you edit is
on the root of the FAT partition that uboot is booting from.

This is /boot/uboot/uEnv.txt on the Debian distribution I use (from
eLinux: Other releases likely
mount things in different locations.

- --
Charles Steinkuehler