2018-09-07 01:50 AM
I am not sure if this is STM32 related question but I noticed one strange behaviour while using STM32 devices with USB composite device and composite device only.
So my device is composite device with three different interfaces (HID). I am transfering data from device to PC and I notice there are periodic glitches in data every 5 seconds (exactly). I sniffed the traffic and I noticed that there is URB_FUNCTION_GET_DESCRIPTOR_FROM_DEVICE from PC side every 5 seconds which obviously is causing glitches.
For additional tests I sniffed traffic on other composite devices and it was same for all of them.
Next I plugged and sniffed non-composite device (Joystick) then I notice there is no URB_FUNCTION_GET_DESCRIPTOR_FROM_DEVICE .
So this periodic 5 second URB_FUNCTION_GET_DESCRIPTOR_FROM_DEVICE happens only with composite devices.
What is even more strange is that this happens only on one specific PC but not on other.
So I am thinking could this be problem with USB controller on motherboard?
Any thoughts on that?
Thanks!
2018-09-07 02:49 AM
Ok so I found a source of that problem. HTC Vive.... if I remove HTC vive software from PC everything works perfect. So obviously their software/drivers are causing problems with all composite devices. I really wonder what is the reason for "scanning" every 5 seconds and interrupting all other devices.