Hi Greg, To debug i have put some printk inside this xhci_handle_event() function for example: xhci_handle_event(){ ..... ........ case TRB_TYPE(TRB_COMPLETION): + printk(KERN_EMERG "TRB_COMPLETION info :%d",le32_to_cpu(event->event_cmd.flags) & TRB_TYPE_BITMASK); handle_cmd_completion(xhci, &event->event_cmd); break; case TRB_TYPE(TRB_TRANSFER): + printk(KERN_EMERG "TRB_TRANSFER info :%d",le32_to_cpu(event->event_cmd.flags) & TRB_TYPE_BITMASK); ret = handle_tx_event(xhci, &event->trans_event); if (ret < 0) xhci->error_bitmask |= 1 << 9; else update_ptrs = 0; break; } Now i am not getting any error with the same script .but i need to give some clarification on this. What may be the reason that error is not coming now?? Thanks Shishir On Wed, Jun 15, 2016 at 5:18 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > On Wed, Jun 15, 2016 at 11:45:36AM +0530, shishir tiwari wrote: >> Hi Greg, >> >> What kernel version is this? >> >>>kernel - 3..4.14 ported on ARM custom board. > > Ouch that is old and obsolete, can you please try 4.6 and see if the > same error happens there? Lots and lots of xhci and other kernel > changes have happened in the many years since 3.4 was released. Not > much we can do about such an old kernel here, sorry. > > greg k-h -- 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