| (3 intermediate revisions by one user not shown) | |||
| Line 4: | Line 4: | ||
<PRE> | <PRE> | ||
cat /sys/devices/bone_capemgr.*/slots | cat /sys/devices/bone_capemgr.*/slots | ||
| + | </PRE> | ||
| + | |||
| + | or for 4.x kernels: | ||
| + | |||
| + | <PRE> | ||
| + | cat /sys/devices/platform/bone_capemgr/slots | ||
</PRE> | </PRE> | ||
| Line 27: | Line 33: | ||
</PRE> | </PRE> | ||
| − | Capes can be enabled or disabled by passing the following parameters to the kernel during boot: | + | Capes can be forcibly enabled or disabled by passing the following parameters to the kernel during boot: |
<PRE> | <PRE> | ||
| Line 35: | Line 41: | ||
Kernel parameters can be specified in the uEnv.txt file. | Kernel parameters can be specified in the uEnv.txt file. | ||
| + | |||
| + | For example, if you want to disable the HDMI interface to free up I/O, mount the FAT partition found on the onboard eMMC where the uEnv.txt file is located: | ||
| + | |||
| + | <PRE> | ||
| + | mount /dev/mmcblk0p1 /media/card | ||
| + | </PRE> | ||
| + | |||
| + | Add add the following to the uEnv.txt file: | ||
| + | <PRE> | ||
| + | optargs=quiet capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN | ||
| + | </PRE> | ||
| + | |||
| + | BB-BONELT-HDMI is the on-board HDMI interface. BB-BONELT-HDMIN is the same interface but with no audio. If only the BB-BONELT-HDMI interface overlay is disabled, the BB-BONELT-HDMIN is loaded instead hence the requirement to disable both. | ||
| + | |||
| + | Then umount and reboot the bone. | ||
| + | |||
| + | Now, when the list of overlays are displayed, the Bone-Black-HDMI & Bone-Black-HDMIN interfaces are shown as not loaded (L): | ||
| + | |||
| + | <PRE> | ||
| + | 0: 54:PF--- | ||
| + | 1: 55:PF--- | ||
| + | 2: 56:PF--- | ||
| + | 3: 57:PF--- | ||
| + | 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G | ||
| + | 5: ff:P-O-- Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI | ||
| + | 6: ff:P-O-- Bone-Black-HDMIN,00A0,Texas Instrument,BB-BONELT-HDMIN | ||
| + | </PRE> | ||
To display the overlays currently enabled by the cape manager, type:
cat /sys/devices/bone_capemgr.*/slots
or for 4.x kernels:
cat /sys/devices/platform/bone_capemgr/slots
On a default Beaglebone Black, it should show:
0: 54:PF--- 1: 55:PF--- 2: 56:PF--- 3: 57:PF--- 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G 5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
The format of output is:
Slot Number: Slot I2C Client Address: [P]robed Flag Probe [F]ailed Flag [O]verride Flag [l]oading Flag [L]oaded Flag
Capes can be forcibly enabled or disabled by passing the following parameters to the kernel during boot:
capemgr.enable_partno=BB-CAPENAME capemgr.disable_partno=BB-CAPENAME
Kernel parameters can be specified in the uEnv.txt file.
For example, if you want to disable the HDMI interface to free up I/O, mount the FAT partition found on the onboard eMMC where the uEnv.txt file is located:
mount /dev/mmcblk0p1 /media/card
Add add the following to the uEnv.txt file:
optargs=quiet capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN
BB-BONELT-HDMI is the on-board HDMI interface. BB-BONELT-HDMIN is the same interface but with no audio. If only the BB-BONELT-HDMI interface overlay is disabled, the BB-BONELT-HDMIN is loaded instead hence the requirement to disable both.
Then umount and reboot the bone.
Now, when the list of overlays are displayed, the Bone-Black-HDMI & Bone-Black-HDMIN interfaces are shown as not loaded (L):
0: 54:PF--- 1: 55:PF--- 2: 56:PF--- 3: 57:PF--- 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G 5: ff:P-O-- Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI 6: ff:P-O-- Bone-Black-HDMIN,00A0,Texas Instrument,BB-BONELT-HDMIN