On Mon, 4 Oct 2010, James wrote: > Thanks. > > Can you explain in laymans terms how badly out of spec it is? > I doubt RCA will fix it because it one of their older products. Well, section 5.5.3 of the USB-2.0 specification says this: An endpoint for control transfers specifies the maximum data payload size that the endpoint can accept from or transmit to the bus. The allowable maximum control transfer data payload sizes for full-speed devices is 8, 16, 32, or 64 bytes; for high-speed devices, it is 64 bytes and for low-speed devices, it is 8 bytes. It also says: All Host Controllers are required to have support for 8-, 16-, 32-, and 64-byte maximum data payload sizes for full-speed control endpoints, only 8-byte maximum data payload sizes for low-speed control endpoints, and only 64-byte maximum data payload size for high-speed control endpoints. No Host Controller is required to support larger or smaller maximum data payload sizes. The VR5220 is a high-speed device, but its maximum data payload size for the control endpoint is 32. Hence no host computer is obliged to support it. In addition, the device appeared to fail completely when used at full speed. There wasn't enough information in your dmesg log to tell exactly what happened, but nevertheless, high-speed devices are required to have a certain minimum functionality when used at full speed. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
