I have a problem with Qt and reading bytes from the serial port.

I have a QTimer at 100 mS. This timerhandler call's read() on Linux or
ReadFile() on windows in order to read bytes from the serial port.

Everything works well except when I put some load on the computer.
For example, I get datacorruption on the serial port when I plug a USB-stick into the computer (on Linux).
I get also data corruption when I open other applications (on windows).

I tried with a real COM-port and with a RS-232 to USB converter. Same result.

When I don't use Qt but instead use a console program that only uses the standard C-library,
no datacorruption occurs, even under heavy load conditions.

I lowered the amount of bytes sent to the pc from 9000 bytes/sec. to 1000 bytes/sec. Same result.

Any ideas?

Are there any known problems of mixing calls to read() or ReadFile() and Qt?