Question

I set my report size to 64 bytes and want to stream single reports (say 2 for now) to the host. My understanding is that there is a ReadFile buffer where these reports can sit. At the host, I have a 64 byte buffer that I use to read single reports. If I send one report from the device, the host reads it fine. If I use two ReadFiles in a loop, the second ReadFile times out. The device is sending two reports. I don’t know if they’re getting on the ReadFile buffer at the same time, so when the host reads the end point for the first report, the buffer gets purged and I lose the second report? If there are indeed 2 reports on the ReadFile buffer, do I need to read them both at once? How would I know how many reports are on the buffer?

Answer 1

ReadFile reads as many reports as there are in the HID driver’s ring buffer up to the numberOfBytesToRead parameter.