Hi. linux-usb and linux-rt experts. > > On 21-08-02 17:35:01, Jeaho Hwang wrote: > > Hi. > > > > We found an infinite loop inside the function hw_ep_set_halt > > (drivers/usb/chipidea/udc.c) if a cablle is repeatedly > > connnected/disconnected while ping through RNDIS with chipidea USB device. > > > > Using ftrace tracing, we found that hw_ep_set_halt is called due to error > > return of hw_ep_prime(drivers/usb/chipidea/udc.c:202) which is called from > > isr_tr_complete_handler -> isr_setup_status_phase -> _ep_queue. > > > > The comment of function hw_ep_prime says (execute without interruption) but > > timer interrupt is occurred while hw_ep_prime is executing. We believe that > > the interrupt causes an error return of hw_ep_prime. We tried to protect > > hw_ep_prime from irqs and then no case of the infinite loop is occurred. > > > > I want ask if it is appropriate way that turning off irq inside (threaded) > > irq handlers. And should we explicitly turn off irqs before calling > > hw_ep_prime? > > > > Jeaho, do you use RT-Linux or standard Linux? The function hw_ep_prime is > only called at udc_irq which is registered as top-half irq handlers. > Why the timer interrupt is occurred when hw_ep_prime is executing? We use preempt_RT so timer interrupt could be occurred. Now I found out that forced threaded irq handler disables local irq on standard linux so It is a linux-rt issue. Then should I make patch which disables local irqs during hw_ep_prime for RT kernel and suggest it to linux-rt maintainers? Thanks for a kind answer Peter. > > -- > > Thanks, > Peter Chen > -- 황재호, Jay Hwang, linux team manager of RTst 010-7242-1593
