3.2.6. FAQs

Q: How to let Linux not load kernel modules automatically during system boot time?

A: Add the module name into the modprobe blacklist in file /etc/modprobe.d/modprobe.conf. For example,

# cat /etc/modprobe.d/modprobe.conf
blacklist musb_am335x

Q: How to disable a peripheral then enable it again?

A: Use its driver’s bind/unbind sysfs entries. For example, to disable rtc on AM57x,

root@dra7xx-evm:~# find /sys -name unbind | grep rtc
/sys/bus/platform/drivers/omap_rtc/unbind
root@dra7xx-evm:~# cd /sys/bus/platform/drivers/omap_rtc/
root@dra7xx-evm:/sys/bus/platform/drivers/omap_rtc# ls
48838000.rtc  bind          module        uevent        unbind
root@dra7xx-evm:/sys/bus/platform/drivers/omap_rtc# echo 48838000.rtc > unbind
root@dra7xx-evm:/sys/bus/platform/drivers/omap_rtc#

to enable it again,

root@dra7xx-evm:/sys/bus/platform/drivers/omap_rtc# echo 48838000.rtc > bind
[ 7792.863975] omap_rtc 48838000.rtc: already running
[ 7792.869822] omap_rtc 48838000.rtc: rtc core: registered 48838000.rtc as rtc1
root@dra7xx-evm:/sys/bus/platform/drivers/omap_rtc#