Hello guys,
I've found a following problems on BeagleBoard and Kernel 3.0.8 with
gadget serial driver.
Attached is a small program, which opens gadget serial tty at
/dev/ttyGS0. USB is NOT connected to host. Then it fills it's output
fifo up. Before closing, it flushes the output fifo. But despite that,
call to close function on last line blocks for 15seconds!
To me it looks like fifo flushing doesn't work. If I do this on regular
serial port on PC and if I remove output fifo flushing, close also
blocks (as I have flow control set). But if the flushing is present,
close returns immediately on PC.
On gadget serial, it always block for 15s.
So it looks to me like a bug in gadget serial driver. Or is there any
other cleanup, which I should do? Or at least some option how to lower
the timeout value?
thank you and best regards
Petr Masek
////////////////////////////////////////////////////////////////////////////////
#include <stdio.h>
#include <string.h>
#include <stdio.h>
#include <termios.h>
#include <fcntl.h>
#include <errno.h>
int main(void)
{
int fd = open("/dev/ttyGS0", O_NOCTTY | O_RDWR | O_NONBLOCK);
if (fd < 0) {
printf("Serial device open error!\n");
return -1;
}
struct termios newtio;
bzero(&newtio,sizeof(struct termios));
newtio.c_cflag = B9600 | CS8 | CRTSCTS | CLOCAL | CREAD |
NOFLSH;
newtio.c_iflag = IGNPAR;
newtio.c_oflag = 0;
newtio.c_lflag = 0;
newtio.c_cc[VMIN] = 0;
newtio.c_cc[VTIME] = 0;
tcsetattr(fd,TCSANOW,&newtio);
int ret = 0;
while (ret >= 0) {
const char buffer[32] = "Hello World!\n";
ret = write(fd, buffer, strlen(buffer));
if ((ret < 0) && (errno == EWOULDBLOCK)) printf("FIFO Full!\n");
}
tcflush(fd, TCOFLUSH);
close(fd);
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