The Bus Frequency driver is used to slow down DDR, AHB, and AXI bus frequency in the SoC when the IPs which need high bus frequency are not working.
This saves the power consumption in Android early suspend mode significantly (playing audio with screen off). In this release, the bus frequency driver is enabled by default. If you want to enable or disable it, perform the following command in the console:
$ echo 0 > /sys/bus/platform/drivers/imx6_busfreq/busfreq.x/enable
$ echo 1 > /sys/bus/platform/drivers/imx6_busfreq/busfreq.x/enable
Note that if you are using Ethernet, the up operation enables the FEC clock and force bus frequency to be high. That means you cannot go into low bus mode anymore, regardless whether the Ethernet cable is plugged or unplugged. Therefore, if you want the system to go into the low bus mode, you must do ‘netcfg eth0 down’ to shut down the FEC manually. If you want to
use FEC again, do ‘netcfg eth0 up’ manually. When FEC is shut down with clock gated, the PHY cannot detect your cable in/out events.