Hi Hans de Goede, Sarah, Mathias, This is about a regression caused by commit a82b76f7f usb: Reset USB-3 devices on USB-3 link bounce. When we do some stress remote wakeup tests with usb3 internal roothub autosuspend enabled, it's found that hub thread calling the port_event() may run before handle_port_status() clears the PLC. Thus, port_event() hits the condition of PLC && U0 && Superspeed and wrongly reset the device. Things happen like this: 1. device initiates the resume 2. xHCI receives the port change, handle_port_status() resume the roothub. portsc is in RESUME and set link to U0. 3. hub_active() finds portsc in RESUME state and sets the hub->change_bits and kick the hub. 4. link change RESUME->U0 happens, but irq is not generated or processed yet. 5. port_event() finds portsc is 0x401203 (PLC && U0), and reset the device. 6. irq is generated now for point 4. But it's too late. The problem is that port_event() falls in the gap between RESUME->U0 transtion (portsc 0x401203) and port change irq is generated and processed. I'd say this is a regression of commit a82b76f7 due to the PLC && U0 && Superspeed condition can also be met in remote wakeup case. Do you have a suggestion to fix the issue? Or should we revert this commit? Thanks Jincan -- 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
