以下代码在 Windows 中对我有效，但在 Linux 中不起作用。我使用的是同一台 PC，两个操作系统都是本机安装的。我不使用虚拟机。我需要在 Linux 上工作。我尝试过不同的 linux 发行版，但在任何地方都无法使用。
// In the main class:
QSerialPortInfo info = XXXX; // Generally in Linux: /dev/ttyUSB0, in win: COM1
QSerialPort serial;
QObject::connect(&serial, SIGNAL(readyRead()), this, SLOT(onReadyRead()), Qt::DirectConnection);
QObject::connect(&serial, SIGNAL(bytesWritten(qint64)), this, SLOT(onBytesWritten(qint64)), Qt::DirectConnection);
QObject::connect(&serial, SIGNAL(error(QSerialPort::SerialPortError)), this, SLOT(onError(QSerialPort::SerialPortError)), Qt::DirectConnection);
// Slot
void MyClass::onReadyRead()
{
qDebug()<<"Signal onReadyRead";
buffer_mutex.lock();
buffer += serial.readAll();
qDebug()<<"Read: "<<qstr_to_hexstr(buffer);
bufferNotEmpty.wakeAll();
buffer_mutex.unlock();
}
void MyClass::onError(QSerialPort::SerialPortError error) {
qCritical()<<"Serial Port Error: "<<(int)error;
}
void MyClass::onBytesWritten(qint64 size){
qDebug()<<"onBytesWritten: "<<size;
}
// In another place I did:
serial.setPort(info);
if(!serial.open(QIODevice::ReadWrite))
return false;
qDebug()<<"Init Setting!...";
if(!serial.setBaudRate(QSerialPort::Baud9600))
qCritical()<<"Error in setBaudRate";
if(!serial.setDataBits(QSerialPort::Data8))
qCritical()<<"Error in setDataBits";
if(!serial.setParity(QSerialPort::EvenParity))
qCritical()<<"Error in setParity";
if(!serial.setStopBits(QSerialPort::OneStop))
qCritical()<<"Error in setStopBits";
if(!serial.setFlowControl(QSerialPort::SoftwareControl))
qCritical()<<"Error in setFlowControl";
if(!serial.setDataTerminalReady(true))
qCritical()<<"Error in setDataTerminalReady";
qDebug()<<"Setting ready!...";
如果发送 1 个字节，设备会响应并正确发送数据。
例子：
// In the main class:
const char enq[2] = {0x05, '\0'};
serial.write (enq);
// In onReadyRead:
serial.readAll(); // Works on Win / Linux
如果发送超过 1 字节的设备在 linux 中不响应请求。
例子：
// In the main class:
const char command[6] = {0x02, 'S', '1', 0x03, 'a', '\0'};
serial.write(command);
// In onReadyRead
serial.readAll(); // Works only in Win
此事件仅在 Windows 中触发。在 linux 中它永远不会工作，没有收到或以错误的格式到达，并且永远无法识别远程设备。
我在 Windows 中的登录：
{Debug} Init Setting!...
{Debug} Setting ready!...
{Debug} Write: " 0x05 "
{Debug} onBytesWritten: 1
{Debug} buffer wait!...
{Debug} Signal onReadyRead
{Debug} Read: " 0x02 `@ 0x03 #"
{Debug} buffer size: 5
{Critical} Serial Port Error: 0
{Debug} Write: " 0x02 S1 0x03 a"
{Debug} onBytesWritten: 5
{Debug} buffer wait!...
{Debug} Signal onReadyRead
{Debug} Read: " 0x02 S100 0x0A 00000000000000000 0x0A 00000479"
{Debug} buffer size: 32
{Debug} buffer wait!...
{Debug} Signal onReadyRead
{Debug} Read: " 0x02 S100 0x0A 00000000000000000 0x0A 00000479 0x0A 00000 0x0A 00000330 0x0A 00000 0x0A 0061 0x0A 0000 0x0A "
{Debug} buffer size: 64
{Debug} Signal onReadyRead
{Debug} buffer wait!...
{Debug} Read: " 0x02 S100 0x0A 00000000000000000 0x0A 00000479 0x0A 00000 0x0A 00000330 0x0A 00000 0x0A 0061 0x0A 0000 0x0A X-XXXXXXXX 0x0A XXXXXXXXX 0x0A 221715 0x0A 120414 0x0A 0x03 0x1B "
{Debug} buffer size: 103
{Critical} Serial Port Error: 0
（我将设备的实际响应替换为“X”字符）
我在 Linux 中的登录：
{Debug} Init Setting!...
{Debug} Setting ready!...
{Debug} Write: " 0x05 "
{Debug} onBytesWritten: 1
{Debug} buffer wait!...
{Debug} Signal onReadyRead
{Debug} Read: " 0x02 `@ 0x03 #"
{Debug} buffer size: 5
{Critical} Serial Port Error: 0
{Debug} Write: " 0x02 S1 0x03 a"
{Debug} onBytesWritten: 5
{Debug} buffer wait!...
{Debug} buffer wait!...
{Debug} buffer wait!...
{Debug} buffer wait!...
{Debug} buffer wait!...
{Debug} buffer wait!...
{Debug} buffer wait!...
{Debug} buffer wait!...
{Debug} buffer wait!...
{Debug} buffer wait!...
{Debug} timeout!... (15 sec for timeout)
USB串口适配器：CH340
In Windows: USB\VID_1A86&PID_7523&REV_0254
In Linux:
Apr 13 01:16:58 kali kernel: [47844.260136] usb 2-1: new full-speed USB device number 16 using uhci_hcd
Apr 13 01:16:58 kali kernel: [47844.428098] usb 2-1: New USB device found, idVendor=1a86, idProduct=7523
Apr 13 01:16:58 kali kernel: [47844.428115] usb 2-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
Apr 13 01:16:58 kali kernel: [47844.428126] usb 2-1: Product: USB2.0-Ser!
Apr 13 01:16:58 kali kernel: [47844.431268] ch341 2-1:1.0: ch341-uart converter detected
Apr 13 01:16:58 kali kernel: [47844.445398] usb 2-1: ch341-uart converter now attached to ttyUSB0
Apr 13 01:16:58 kali mtp-probe: checking bus 2, device 16: "/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1"
Apr 13 01:16:58 kali mtp-probe: bus: 2, device: 16 was not an MTP device
PD：对不起我的英语，尽量用谷歌翻译做到最好:(...
更多信息1：
Apr 13 04:10:55 kali kernel: [ 4872.627980] tty ttyUSB0: serial_write - 1 byte(s)
Apr 13 04:10:55 kali kernel: [ 4872.629763] tty ttyUSB0: serial_chars_in_buffer
Apr 13 04:10:55 kali kernel: [ 4872.629778] tty ttyUSB0: serial_wait_until_sent
Apr 13 04:10:55 kali kernel: [ 4872.638252] tty ttyUSB0: serial_chars_in_buffer
Apr 13 04:10:55 kali kernel: [ 4872.638267] tty ttyUSB0: serial_write_room
Apr 13 04:10:55 kali kernel: [ 4872.638278] tty ttyUSB0: serial_chars_in_buffer
Apr 13 04:10:55 kali kernel: [ 4872.638287] tty ttyUSB0: serial_write_room
Apr 13 04:10:55 kali kernel: [ 4872.639438] tty ttyUSB0: serial_chars_in_buffer
Apr 13 04:10:55 kali kernel: [ 4872.639458] tty ttyUSB0: serial_write_room
Apr 13 04:10:55 kali kernel: [ 4872.639475] tty ttyUSB0: serial_chars_in_buffer
Apr 13 04:10:55 kali kernel: [ 4872.639488] tty ttyUSB0: serial_write_room
Apr 13 04:10:56 kali kernel: [ 4873.641799] tty ttyUSB0: serial_ioctl - cmd 0x540b
Apr 13 04:10:56 kali kernel: [ 4873.646884] tty ttyUSB0: serial_write - 5 byte(s)
Apr 13 04:10:56 kali kernel: [ 4873.647152] ch341-uart ttyUSB0: ch341_update_line_status - multiple status change
Apr 13 04:10:56 kali kernel: [ 4873.647176] ch341-uart ttyUSB0: ch341_update_line_status - delta=0x01
Apr 13 04:10:56 kali kernel: [ 4873.647384] tty ttyUSB0: serial_chars_in_buffer
Apr 13 04:10:56 kali kernel: [ 4873.647401] tty ttyUSB0: serial_wait_until_sent
Apr 13 04:10:56 kali kernel: [ 4873.649144] ch341-uart ttyUSB0: ch341_update_line_status - multiple status change
Apr 13 04:10:56 kali kernel: [ 4873.649166] ch341-uart ttyUSB0: ch341_update_line_status - delta=0x01
Apr 13 04:10:56 kali kernel: [ 4873.692152] ch341-uart ttyUSB0: ch341_update_line_status - multiple status change
Apr 13 04:10:56 kali kernel: [ 4873.692170] ch341-uart ttyUSB0: ch341_update_line_status - delta=0x01
Apr 13 04:10:56 kali kernel: [ 4873.694133] ch341-uart ttyUSB0: ch341_update_line_status - multiple status change
Apr 13 04:10:56 kali kernel: [ 4873.694148] ch341-uart ttyUSB0: ch341_update_line_status - delta=0x01
我重建 ch341.c 并添加：
if (!delta)
return;
dev_info(&port->dev, "%s - delta=0x%02X\n", __func__, delta); // <---- New Line
if (delta & CH341_BIT_CTS)
port->icount.cts++;
if (delta & CH341_BIT_DSR)
port->icount.dsr++;
if (delta & CH341_BIT_RI)
port->icount.rng++;
if (delta & CH341_BIT_DCD) {
port->icount.dcd++;
tty = tty_port_tty_get(&port->port);
if (tty) {
usb_serial_handle_dcd_change(port, tty,
status & CH341_BIT_DCD);
tty_kref_put(tty);
}
}
日志中的 delta=0x01 是标志：
#define CH341_BIT_CTS 0x01
更多信息2：
在写/读线程中，我希望在 onReadyRead 上运行 wakeAll。如果您在检查缓冲区是否为空之前通过第二次 readAll 。例子：
// In the main class:
QWaitCondition bufferNotEmpty;
// In my function write/read:
serial.write(data, size);
buffer_mutex.lock();
while(time(NULL)-timeStart<timeoutWait && serial.isOpen()) {
buffer += serial.readAll();
if(buffer.count()>0){
qDebug()<<"buffer size: "<<buffer.count();
//Interprete the buffer here...
if(bufferComplete)
break;
}
qDebug()<<"buffer wait!...";
bufferNotEmpty.wait(&buffer_mutex, 1000);
}
buffer.clear();
buffer_mutex.unlock();
更多信息3：
我的内核是 3.12.6，但我从 GitHub 更新了这个文件并重建了这个驱动程序：
https://github.com/torvalds/linux/blob/master/drivers/usb/serial/ch341.c https://github.com/torvalds/linux/blob/master/drivers/usb/serial/usb-serial .c （提交 d9a38a8741fdffabc32e6d0943b1cdcf22712bec）