I reported here: https://bugreports.qt-project.org/browse/QTBUG-38305 But just migrate my APP to ANSI C and is exactly the same. My code test in ANSI C: #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <termios.h> #include <unistd.h> #include <errno.h> #include <stdio.h> #include <string.h> #include <ctype.h> #include <pthread.h> #include <stdlib.h> #include <time.h> #define STX (0x02) #define ETX (0x03) #define ENQ (0x05) #define ACK (0x06) #define NAK (0x15) #define SEP (0x0A) int serial = -1; int finnish = 0; char *buffer = NULL; size_t buffer_size = 0; size_t buffer_len = 0; const char enq[1] = {ENQ}; const char ack[1] = {ACK}; const char nak[1] = {NAK}; pthread_cond_t buffer_no_empty = PTHREAD_COND_INITIALIZER; pthread_mutex_t buffer_mutex = PTHREAD_MUTEX_INITIALIZER; static void debug_str(const char *str, size_t size) { int i; for(i = 0; i < size; ++i) if(isprint(str[i]) && !iscntrl(str[i])) printf("%c", (char)str[i]); else printf(" 0x%02X ", (unsigned char) str[i]); printf("\n"); } static void flush() { if(serial<0) return; tcflush(serial, TCIFLUSH); tcflush(serial, TCIOFLUSH); tcflush(serial, TCOFLUSH); } static void openPort(const char *port) { serial = open(port, O_RDWR | O_NOCTTY | O_NONBLOCK); if(serial<0) { printf("Error %u from serial open: %s\n", errno, strerror(errno)); return ; } struct termios tty; memset(&tty, 0, sizeof(tty)); // Set Baud Rate cfsetospeed (&tty, B9600); cfsetispeed (&tty, B9600); tty.c_cflag |= PARENB; tty.c_cflag &= ~(PARODD | CSTOPB | CSIZE); tty.c_cflag |= CS8; tty.c_cflag |= CLOCAL; tty.c_cflag |= CREAD; tty.c_iflag |= (IXON | IXOFF | IXANY); flush(); if ( tcsetattr(serial, TCSANOW, &tty) != 0 ) printf("Error %d from tcsetattr: %s\n", errno, strerror(errno)); flush(); } #define valid_buffer() (buffer_size>3 && buffer[0]==STX && buffer[buffer_size-2] == ETX) static void* thread_read(void* dummy) { unsigned char buf; while(!finnish) { int n = read(serial, &buf, 1); if(n>0) { pthread_mutex_lock(&buffer_mutex); if(buf == ENQ) { printf("Recive ENQ, sending ACK\n"); write(serial, ack, 1); pthread_mutex_unlock(&buffer_mutex); continue; } if(buffer_size == buffer_len) { buffer_len *= 2; buffer = realloc(buffer, (size_t)buffer_len); } buffer[buffer_size] = buf; buffer_size += 1; printf("Buffer: "); debug_str(buffer, buffer_size); if(valid_buffer()) { printf("Signal buffer_no_empty\n"); pthread_cond_signal(&buffer_no_empty); } pthread_mutex_unlock(&buffer_mutex); }else if(n<0 && errno!=11) { printf("Error %d from serial read: %s\n", errno, strerror(errno)); } } return NULL; } static void send_and_read(const char *data, size_t size, int timeout, char **recv, size_t *size_recv) { printf("Write: "); debug_str(data, size); write(serial, data, size); time_t startTime = time(NULL); struct timespec ts; clock_gettime(CLOCK_REALTIME, &ts); ts.tv_sec += timeout; printf("Wait response...\n"); pthread_mutex_lock(&buffer_mutex); while(!valid_buffer() && time(NULL)-startTime<timeout-1) pthread_cond_timedwait(&buffer_no_empty, &buffer_mutex, &ts); if(valid_buffer()) { *recv = malloc(buffer_size+1); *size_recv = buffer_size; memcpy(*recv, buffer, buffer_size); (*recv)[buffer_size]='\0'; printf("Read:"); debug_str(*recv, buffer_size); }else{ printf("Timeout...\n"); *recv = NULL; *size_recv = 0; } buffer_size = 0; memset(buffer, 0, buffer_len); pthread_mutex_unlock(&buffer_mutex); } int main(){ openPort("/dev/ttyUSB0"); if(serial>0) { buffer = malloc(1024); buffer_len = 1024; pthread_t thread; pthread_create(&thread, NULL, thread_read, NULL); char *test = NULL; size_t s = 0; send_and_read(enq, 1, 15, &test, &s); if(s>0) printf("Test status: OK\n"); else printf("Test status: Fail\n"); sleep(3); //Pause... char command[5] = {STX, 'S', '1', ETX, 'a'}; send_and_read(command, 5, 15, &test, &s); if(s>0) printf("Test command: OK\n"); else printf("Test command: Fail\n"); finnish = 1; void *dummy; pthread_join(thread, &dummy); close(serial); free(buffer); } } My Log of APP: Write: 0x05 Wait response... Buffer: 0x02 Buffer: 0x02 ` Buffer: 0x02 `@ Buffer: 0x02 `@ 0x03 Buffer: 0x02 `@ 0x03 # Signal buffer_no_empty Read: 0x02 `@ 0x03 # Test status: OK Write: 0x02 S1 0x03 a Wait response... Timeout... Test command: Fail My syslog: Apr 14 00:09:44 kali kernel: [14827.112964] tty ttyUSB0: serial_open Apr 14 00:09:44 kali kernel: [14827.112981] usb 1-1: ch341_control_in(c0,5f,0000,0000,ef484b00,8) Apr 14 00:09:44 kali kernel: [14827.114572] usb 1-1: ch341_control_out(40,a1,0000,0000) Apr 14 00:09:44 kali kernel: [14827.115557] usb 1-1: ch341_control_out(40,9a,1312,b202) Apr 14 00:09:44 kali kernel: [14827.116592] usb 1-1: ch341_control_out(40,9a,0f2c,000c) Apr 14 00:09:44 kali kernel: [14827.117595] usb 1-1: ch341_control_in(c0,95,2518,0000,ef484b00,8) Apr 14 00:09:44 kali kernel: [14827.118579] usb 1-1: ch341_control_out(40,9a,2518,0050) Apr 14 00:09:44 kali kernel: [14827.119572] usb 1-1: ch341_control_in(c0,95,0706,0000,ef484a40,8) Apr 14 00:09:44 kali kernel: [14827.120608] usb 1-1: ch341_control_out(40,a1,501f,d90a) Apr 14 00:09:44 kali kernel: [14827.121572] usb 1-1: ch341_control_out(40,9a,1312,b202) Apr 14 00:09:44 kali kernel: [14827.122569] usb 1-1: ch341_control_out(40,9a,0f2c,000c) Apr 14 00:09:44 kali kernel: [14827.123566] usb 1-1: ch341_control_out(40,a4,ff9f,0000) Apr 14 00:09:44 kali kernel: [14827.124602] usb 1-1: ch341_control_in(c0,95,0706,0000,ef484a40,8) Apr 14 00:09:44 kali kernel: [14827.125572] usb 1-1: ch341_control_out(40,a4,ff9f,0000) Apr 14 00:09:44 kali kernel: [14827.126567] usb 1-1: ch341_control_out(40,9a,1312,b202) Apr 14 00:09:44 kali kernel: [14827.127566] usb 1-1: ch341_control_out(40,9a,0f2c,000c) Apr 14 00:09:44 kali kernel: [14827.128597] ch341-uart ttyUSB0: ch341_open - submitting interrupt urb Apr 14 00:09:44 kali kernel: [14827.128649] usb 1-1: ch341_control_out(40,a4,ff9f,0000) Apr 14 00:09:44 kali kernel: [14827.129658] tty ttyUSB0: serial_ioctl - cmd 0x540b Apr 14 00:09:44 kali kernel: [14827.129678] tty ttyUSB0: serial_ioctl - cmd 0x540b Apr 14 00:09:44 kali kernel: [14827.129691] tty ttyUSB0: serial_ioctl - cmd 0x540b Apr 14 00:09:44 kali kernel: [14827.129706] tty ttyUSB0: serial_ioctl - cmd 0x5401 Apr 14 00:09:44 kali kernel: [14827.129720] tty ttyUSB0: serial_ioctl - cmd 0x5402 Apr 14 00:09:44 kali kernel: [14827.129733] tty ttyUSB0: serial_set_termios Apr 14 00:09:44 kali kernel: [14827.129746] usb 1-1: ch341_control_out(40,9a,1312,b202) Apr 14 00:09:44 kali kernel: [14827.130559] ch341-uart ttyUSB0: ch341_update_line_status - multiple status change Apr 14 00:09:44 kali kernel: [14827.130570] ch341-uart ttyUSB0: ch341_update_line_status - delta=0x02 Apr 14 00:09:44 kali kernel: [14827.130612] usb 1-1: ch341_control_out(40,9a,0f2c,000c) Apr 14 00:09:44 kali kernel: [14827.131589] usb 1-1: ch341_control_out(40,a4,ff9f,0000) Apr 14 00:09:44 kali kernel: [14827.132553] ch341-uart ttyUSB0: ch341_update_line_status - multiple status change Apr 14 00:09:44 kali kernel: [14827.132571] ch341-uart ttyUSB0: ch341_update_line_status - delta=0x02 Apr 14 00:09:44 kali kernel: [14827.133388] tty ttyUSB0: serial_ioctl - cmd 0x5401 Apr 14 00:09:44 kali kernel: [14827.133411] tty ttyUSB0: serial_ioctl - cmd 0x540b Apr 14 00:09:44 kali kernel: [14827.133427] tty ttyUSB0: serial_ioctl - cmd 0x540b Apr 14 00:09:44 kali kernel: [14827.133440] tty ttyUSB0: serial_ioctl - cmd 0x540b Apr 14 00:09:44 kali kernel: [14827.134087] tty ttyUSB0: serial_write - 1 byte(s) Apr 14 00:09:47 kali kernel: [14830.144091] tty ttyUSB0: serial_write - 5 byte(s) Apr 14 00:09:47 kali kernel: [14830.152441] ch341-uart ttyUSB0: ch341_update_line_status - multiple status change Apr 14 00:09:47 kali kernel: [14830.152452] ch341-uart ttyUSB0: ch341_update_line_status - delta=0x01 Apr 14 00:09:47 kali kernel: [14830.154426] ch341-uart ttyUSB0: ch341_update_line_status - multiple status change Apr 14 00:09:47 kali kernel: [14830.154433] ch341-uart ttyUSB0: ch341_update_line_status - delta=0x01 Apr 14 00:10:02 kali kernel: [14845.144415] tty ttyUSB0: serial_close Apr 14 00:10:02 kali kernel: [14845.144432] tty ttyUSB0: serial_chars_in_buffer Apr 14 00:10:02 kali kernel: [14845.144442] tty ttyUSB0: serial_wait_until_sent Apr 14 00:10:02 kali kernel: [14845.147914] usb 1-1: ch341_read_int_callback - urb shutting down: -2 Apr 14 00:10:02 kali kernel: [14845.149723] tty ttyUSB0: serial_cleanup I think it's not the fault of QT ... 2014-04-13 21:14 GMT-04:30 Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>: > On Sun, Apr 13, 2014 at 08:51:56PM -0430, Kijam López wrote: >> The following code works for me correctly in Windows, but Linux does >> not work. I am using the same PC, both operating systems are installed >> native. I do not use virtual machine. I need to work on Linux. I have >> tried in different linux distributions and does not work anywhere. > > <snip> > > Sounds like a Qt issue, what is the status of the bug you filed with > those developers? > > greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html