select API time out on 9600 baud rate - linux

Question

I am reading the data from the serial/UART, with 9600 baud rate (my 115200 baud rate is working fine)
I wrote the below code, but the select API every time gives time out, it requires timeout more than 2 seconds, that is not desirable. As I have 2048 bytes of data so within 100 ms I should able to get some data, but I think select API is not receiving interrupts, even though Rx buffer of serial has some data to process.
NOTE: the same piece of code working fine on beaglebone black, while not on intel atom-3900 / Kernel used is Linux-intel 4.9.
Thanks for the anticipation
code:
int main(void)
{
int ret;
char buf[1280];
fd_set m_Inputs; // fd_set for the select call for com input
int m_maxFD; // max FD for select() call.
struct timeval tv;
/*Open Serial port in non blocking mode*/
int fd1;
fd1 = open("/dev/ttyS1", O_RDWR | O_NOCTTY | O_NONBLOCK);
/* get the termios structure */
struct termios options;
tcgetattr(fd1, &options); // Get the current options for the port...
// Set the baud rates...
cfsetispeed(&options, B9600);
cfsetospeed(&options, B9600);
// Enable the receiver and set local mode...
options.c_cflag |= (CLOCAL | CREAD | CS8);
options.c_cflag &= ~PARENB; // ignore parity
options.c_cflag &= ~CSTOPB; // 1 stop bit (2 if set)
options.c_cflag &= ~CSIZE; // clear the size bits
options.c_cflag &= ~CRTSCTS; //No hard flow control
options.c_cflag &= ~HUPCL; //Hang Up on last Close
options.c_cflag |= CS8; // reset the size to 8 bits / char
options.c_cc[VMIN]=1;
options.c_cc[VTIME] = 1;
options.c_oflag = 0;
options.c_lflag = 0; //ICANON;
// Set the new options for the port...
tcsetattr(fd1, TCSANOW, &options);
cout << endl << "FD1 = " << fd1 << endl;
while (1)
{
fd_set rfds; // fd_set for the select call for com input
FD_ZERO(&rfds);
FD_SET(fd1, &rfds);
tv.tv_sec = 0;
tv.tv_usec = 100000;
ret = select(fd1 + 1, &rfds, NULL, NULL, &tv);
if (ret > 0)
{
ret = read(fd1, buf, 127);
buf[ret] = '\0';
cout << buf;
}else{
cout << "Time OUT" << endl;
break;
}
}
return 0;
}