On Thu, 24 Jan 2019, Bin Liu wrote: > > Perhaps it has something to do with the timing of the completion > > interrupts. I don't know anything about how musb works, though. Some > > low-level timing information would be good to see. > > The musb controller driver itself doesn't have a isr BH, so when an ep > interrupt happened, the isr directly processes the urb and called > giveback. I tried to add HCD_BH to the musb hcd .flag, the issue still > happens. I was thinking that maybe some controllers delay some types of completion interrupt until a frame boundary, while other controllers raise all completion interrupts immediately. Alan Stern
