The error TTY TTYHOG indicates that the sending device is ignoring flow control. This error occurs after the hardware FIFO has been accessed and has written to the software buffer. In other words, the tty hog error is logged because the buffer where incoming characters are placed is overflowing. When the buffer is about 3/4's full, the device driver notifies the hardware (in this case tty), to send the XOFF char to the sender to stop sending data (or drop the hardware control line). If the sender continues to send data, and the buffer is not emptied, the device driver flushes the buffer and logs the error message in the error log.
[ Doc Ref: 90605203914682 Publish Date: Aug. 06, 2001]