hi all: i am working on a mips borad with linux-2.6.14. and my board boot up from an initrd and then switch to Nand FLASH as root dev. it also add a power control entry like the /arch/mips/common/power.c do. as follow #define CTL_ACPI 9999 #define ACPI_S1_SLP_TYP 19 #define ACPI_SLEEP 21 static struct ctl_table pm_table[] = { {ACPI_S1_SLP_TYP, "suspend", NULL, 0, 0600, NULL, &pm_do_suspend}, {ACPI_SLEEP, "sleep", NULL, 0, 0600, NULL, &pm_do_sleep}, {CTL_ACPI, "freq", NULL, 0, 0600, NULL, &pm_do_freq}, {0} }; static struct ctl_table pm_dir_table[] = { {CTL_ACPI, "pm", NULL, 0, 0555, pm_table}, {0} }; /* * Initialize power interface */ static int __init pm_init(void) { register_sysctl_table(pm_dir_table, 1); return 0; } __initcall(pm_init); they had worked well before. but this week, out nand flash driver change the driver to new code. and when use the same kernel to bootup ,when switch rootfs by /linuxrc. it get messages "bad magic number for tty struct ..." . but if i manual insmod my flash driiver, it works.and also if ii remove the "register_sysctl_table(pm_dir_table, 1)", it works too. so what will cause this situation? (i have check the flash driver code, not find special code). BTW: the initrd is made with busybox instead of nash. thanks for any hints Best Regards zhuzhenhua