chrome.hid.send的ArrayBuffer大小是否有限制?
问题描述:
docs似乎没有提到任何这样的限制,但当我尝试发送一个64字节长的消息时出现奇怪的错误。所有其他消息传输似乎工作正常。chrome.hid.send的ArrayBuffer大小是否有限制?
不,我认为这是真正的问题有关被问,但这里是我send
万一COMMS
命名空间中的方法有一个明显的错误,我应该知道的:
// Transmits the given data
//
// @param[in] outData, The data to send as an ArrayBuffer
// @param[in] onTxCompleted, The method called on completion of the outgoing transfer. The return
// code is passed as a string.
// @param[in] onRxCompleted, The method called on completion of the incoming transfer. The return
// code is passed as a string along with the response as an ArrayBuffer.
send: function(outData, onTxCompleted, onRxCompleted) {
if (-1 === connection_) {
console.log("Attempted to send data with no device connected.");
return;
}
if (0 == outData.byteLength) {
console.log("Attempted to send nothing.");
return;
}
if (COMMS.receiving) {
console.log("Waiting for a response to a previous message. Aborting.");
return;
}
if (COMMS.transmitting) {
console.log("Waiting for a previous message to finish sending. Aborting.");
return;
}
COMMS.transmitting = true;
chrome.hid.send(connection_, REPORT_ID, outData, function() {
COMMS.transmitting = false;
if (onTxCompleted) {
onTxCompleted(chrome.runtime.lastError ? chrome.runtime.lastError.message : '');
}
if (chrome.runtime.lastError) {
console.log('Error in COMMS.send: ' + chrome.runtime.lastError.message);
return;
}
// Register a response handler if one is expected
if (onRxCompleted) {
COMMS.receiving = true;
chrome.hid.receive(connection_, function(reportId, inData) {
COMMS.receiving = false;
onRxCompleted(chrome.runtime.lastError ? chrome.runtime.lastError.message : '', inData);
});
}
});
}
答
对于一个设备的属性从HidDeviceInfo
改为"maxInputReportSize":64,"maxOutputReportSize":64
,那里似乎不是chrome.hid.send
施加的额外限制。但似乎有些东西是错误的。
使用OP中的方法,我可以成功发送一条消息,提示从设备返回。我目前无法仅发送传出消息。我希望chrome.lastError.message
比Transfer Failed
更详细一些。
什么类型的HID设备?它的USB描述符是什么说最大的数据包大小是? – duskwuff 2014-12-02 19:54:08
不幸的是一个自定义设备。来自HidDeviceInfo对象的属性读取“maxInputReportSize”:64,“maxOutputReportSize”:64 – tarabyte 2014-12-02 20:02:25
设备本身可能有故障吗?你确定它可以接受并正确处理64字节的数据包吗? – duskwuff 2014-12-02 22:01:08