急急急：把控制终端修改为ttyS0系统启动很慢；（ttyS2没有此问题；）
在启动UDEV创建设备里耗时多出了30几秒；（ttyS2没有此问题；）
5.889785] UBIFS: default compressor: lzo
[ 5.889830] UBIFS: reserved for root: 0 bytes (0 KiB)
[ 5.892587] VFS: Mounted root (ubifs filesystem) on device 0:13.
[ 5.895021] Freeing init memory: 444K
[ 36.851033] udevd (522): /proc/522/oom_adj is deprecated, please use /proc/522/oom_score_adj instead.
[ 76.080868] linkdsp: insmod linkdsp dev
[ 76.121543] spifram: max_speed_hz( 40000000),bits_per_word( 8),mode(3)
[ 76.129810] spifram: insmod spi fram dev
[ 76.176900] pmac780h_keys_init
[ 76.185545] pmac780h_keys_probe entry!
[ 76.185625] pmac_init_kbd_data p_kbd=c9d8dd80
[ 76.202816] input: PMAC780h_kbd as /devices/virtual/input/input0
[ 76.203486] Interrupt request : 115 successfully
