Hello.I have been working on program based on LDD3 source tiny_tty driver (and I have problem with reading from device in user space.

Program works perfectly but when I copy data from driver (equivalent to tiny_timer with using tty_flip_buffer_push and tty_insert_flip_string or tty_insert_flip_char )to user space, data return to buffer in writing function .I can not read data in user space (cat /dev/ttty0) and I have no idea where the problem is.