Jan,
Have a question on USB Host controller EHCI on chip I am using.
In host mode It looks like there is too much latency in the read operations to fetch the Queue Head and the transfer descriptors due to extensive traffic in the system. (HREADY is low for a long periods and asserted for short periods).The controller DMA state machine fetches the Queue Head (QH) and the transfer descriptor (qTD) and moves to the state where it would execute the transfer, but it does not execute the transfer if it has the indication that there is not enough time in the current micro frame to execute Asynchronous schedule transfers. In that case the state machine moves back to idle state and reads the QH again, moves to executing the transfer and again it cannot execute the transfer within the current micro frame.
Due to this phenomemon, I see indefinite starvation, so Is it a host controller bug or host controller is not expected to deal with such a slow memory ?
