Hi, While I was working on a device controller driver tested with mass storage, I got a question regarding on the stall condition. For mass storage device, the driver stalls the bulk-in ep when there is an error processing CBW. Then the host will send clear_feature to clear the halt condition. However set_halt in all udc drivers always checks if the IN ep queue is empty, and returns -EAGAIN when the ep queue is not empty. Here comes the problem: A problem with CBW is found. Device stalls bulk-in ep. Host sends clear_feature control transfer. Gadget layer queues error CSW to the bulk-in ep. At this time, the bulk-in ep is halted, there is a CSW request queued in the bulk-in ep, and clear_feature can't be executed as the queue is not empty. They form a dead-lock, and stop working. How did we do to avoid such a situation? Or to break it? -- Leo Li Freescale Semiconductor [EMAIL PROTECTED]
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