QGamePad - Does not detect disconnection - Linux
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Dear guy's
The 11 November 2016 I have reported a problem with QGamePad on Linux (bug report)
Currently (in 2018) it is still not fixed.
The problem:
With the backend "evdev" when the gamepad is disconnected the module doesn't process the event from the driver!It's a real problem because I have to control a heavy robot and it can be dangerous if the remote controller is disconnected because I have no ways to detect it using QGamePad: Nothing is updated on the module when it happens !
The problem is in qevdevgamepadbackend.cpp the signal deviceRemoved() is not emit!. But if you see in readData(), this signal can be emit ...
void QEvdevGamepadDevice::readData() { input_event buffer[32]; int events = 0, n = 0; for (; ;) { events = QT_READ(m_fd, reinterpret_cast<char*>(buffer) + n, sizeof(buffer) - n); if (events <= 0) goto err; n += events; if (n % sizeof(::input_event) == 0) break; } n /= sizeof(::input_event); for (int i = 0; i < n; ++i) processInputEvent(&buffer[i]); return; err: if (!events) { qWarning("Gamepad: Got EOF from input device"); return; } else if (events < 0) { if (errno != EINTR && errno != EAGAIN) { qErrnoWarning(errno, "Gamepad: Could not read from input device"); if (errno == ENODEV) { // device got disconnected -> stop reading delete m_notifier; m_notifier = 0; QT_CLOSE(m_fd); m_fd = -1; } } } }When the gamepad is disconnected, the message "Gamepad: Could not read from input device" appear.
Maybe we just have to add "emit deviceRemoved()" but you need to pass a QString with the device name, maybe that's the reason why it's not finished since two years
Can someone check it please ?
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Hi,
You should add your new findings to the bug report.
-
Dear guy's
The 11 November 2016 I have reported a problem with QGamePad on Linux (bug report)
Currently (in 2018) it is still not fixed.
The problem:
With the backend "evdev" when the gamepad is disconnected the module doesn't process the event from the driver!It's a real problem because I have to control a heavy robot and it can be dangerous if the remote controller is disconnected because I have no ways to detect it using QGamePad: Nothing is updated on the module when it happens !
The problem is in qevdevgamepadbackend.cpp the signal deviceRemoved() is not emit!. But if you see in readData(), this signal can be emit ...
void QEvdevGamepadDevice::readData() { input_event buffer[32]; int events = 0, n = 0; for (; ;) { events = QT_READ(m_fd, reinterpret_cast<char*>(buffer) + n, sizeof(buffer) - n); if (events <= 0) goto err; n += events; if (n % sizeof(::input_event) == 0) break; } n /= sizeof(::input_event); for (int i = 0; i < n; ++i) processInputEvent(&buffer[i]); return; err: if (!events) { qWarning("Gamepad: Got EOF from input device"); return; } else if (events < 0) { if (errno != EINTR && errno != EAGAIN) { qErrnoWarning(errno, "Gamepad: Could not read from input device"); if (errno == ENODEV) { // device got disconnected -> stop reading delete m_notifier; m_notifier = 0; QT_CLOSE(m_fd); m_fd = -1; } } } }When the gamepad is disconnected, the message "Gamepad: Could not read from input device" appear.
Maybe we just have to add "emit deviceRemoved()" but you need to pass a QString with the device name, maybe that's the reason why it's not finished since two years
Can someone check it please ?
I don't see a signal
deviceRemoved()in QtGamePad. The nearest one isconnectedChanged(bool)but that looks indeed like a possible signal in this situation.Have you already tried to patch the code yourself? Due to the lack of a gamepad, I cannot test this myself.
Regards
Edit: Ah, there is a
deviceRemoved()signal in QEvdevGamepadBackend which is used within the backend only for housekeeping. What stays, the signal you need outside isconnectChanged(bool).
