Windows8 RC problem | Cypress Semiconductor
Windows8 RC problem
Is anyone else here using Win8?
I'm testing on the recent Win8 x64 Release Preview (Build8400). This is not the Consumer Preview, it is newer than that.
I have three problems:-
1) Win8 does not always seem to see the FX3 bootloader device at startup if plugged into USB3.
It does see it fine if it is plugged into a USB2.0 legacy port.
But it does not see it at all if plugged into a Rensesas uPD720201 USB3.0 port.
It does sometimes see it if plugged into a ETRON EJ168 motherboard USB3.0 port.
If I boot Win7x64 then both of these same USB ports recognise my device just fine.
OK, back to Win8. I can plug into USB2.0 FS port. Then I can boot my firmware via Control Center.
2) (Still on same USB2.0 port on Win8). My device enumerates as a FS WinUSB Class device (ie. no Windows drivers needed).
I have printfs in the enumeration and it looks fine. It appears in device manager as a WinUSB device OK.
My simple WinUSB test app is able to find the device from it's DeviceInterfaceGUID just fine.
But it performs very slowly, even for USB2.0 FS.
I see approx 1MB/s on a simple bulk transfer benchmark.
This exact same firmware and test app (not a rebuild. it's the exact same files) performs at >40MB/s on USB2.0 FS on Win7 x64
3) I unplug it (still powered, so still my firmware) and re-plug into a USB3.0 port.
It re-enumerates as you would expect. Win8 appears to recognise it as a WinUSB device. It now shows up again in device manager as a "WinUSB Device" that is "working properly". However the same test app now fails. When it calls GetDevicePath passing the same DeviceInterfaceGUID the device is not found. This behaviour is the same regardless of whether I use the ETRON or Renesas controller.
Any suggestions for what might be wrong or what to try next?