[Linux driver]Module insertion error – “version magic ‘2.6.35 SMP mod_unload ‘ should be ‘2.6.35 SMP preempt mod_unload”

If you are getting the module insertion error in kernel , “version magic ‘2.6.35 SMP mod_unload ‘ should be ‘2.6.35 SMP preempt mod_unload”, while loading even a simple character driver , then rebuild your kernel by enabling preempt option , then build the driver module and try inserting .  Set following option in kernel config

[C][Bash]How to get the bash environment variables from a C program?

  C program can use getenv function , which searches the environment list to find the environment variable name, and returns a pointer to the corresponding value string,  for getting the bash environment variables.    eg:  /*This C program is to show that how to get bash variables */ #include <stdio.h>#include <stdlib.h> int main(void){ printf(” %s\n”

[U-boot]How to redirect prints to serial console in uboot

In uboot , there is environment variable called stdout . Set its value to serial  setenv stdout serial Refer common/console.c in uboot directory 

[U-Boot]overlapping section error in u-boot compilation

Error in u-boot compilation “section .bootpg lma 0xeffff000 overlaps previous sections” Reason  –  The text base address macro ,  CONFIG_SYS_TEXT_BASE is using default value . Solution – Define the macro CONFIG_SYS_TEXT_BASE This macro may be defined under some compiler directives. So search for this macro in the config file (eg: include/configs/board_name.h) . If it is there