Uart data corrupt if working with Qt Qml on Allwinner A20 legacy kernel

AneoX

I am working with embed device with Allwinner A20 cortex-a7 cpu.
Qt was build with mali support, to work direct with framebuffer like here, no x11
My app are using uart to recieve data.

If i run own app and (for example) standart Qml Oscilliscope from Qt 5.7 examples simultaneously, data bytes recieved from uart lost or become wrong in my app. I have test with QSerialPort and basic C serial implemintation in my app(like here), same result.
Htop return system load under 0.75(A20 has 2 cores), so looks like a system not fully load.

If i run my app and sysbench --test=cpu --cpu-max-prime=20000 --num-threads=2 run, htop return 100% load on both cores, but my app not lost any data.

SGaist

Hi and welcome to devnet,

Did you check that you are setting up your serial port correctly ?
How do you know whether you got all data ?

AneoX

This post is deleted!

AneoX

@SGaist
Hi!
I am sending 96 bytes packet with CRC every 155ms, data corrupt

SGaist

How are you setting up the QSerialPort you are using for your application ?

AneoX

@SGaist

setPortName("/dev/ttyS1");
setBaudRate(1500000);
setDataBits(8);
setParity(0);
setStopBits(1);
setFlowControl(0);

if (open(QIODevice::ReadWrite))
{

..............

it working well, if run alone

SGaist

You should also check that setBaudRate is successful.

Then are you using in your port in the main thread ? If so, you should move its handling in its own thread.

AneoX

@SGaist
baud is correct, i can see it with logic analyzer
i have made new class inherit from QSerialPort and then

QThread *serialThread = new QThread();
mySerialClass = new MySerialClass();
mySerialClass->moveToThread(serialThread);
serialThread->start();
serialThread->setPriority(QThread::TimeCriticalPriority);

SGaist

I didn't imply that the value was wrong, setBaudRate returns a boolean, that's the return value I suggested to check.

AneoX

only solution is decrease baud rate

SGaist

Nice !

In that case, please mark the thread as solved using the "Topic Tools" button so that other forum users may know a solution has been found :)