* Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> wrote: > Fair enough. > > USB connection is stable enough, unless the user unplugs the > USB cable during debugging. What does the hardware do in this case? The XHCI registers are in the host hardware, so they won't disappear, right? Is there some cable connection status bit we can extract without interrupts? I.e. if there's any polling component then it would be reasonable to add an error component: poll the status and if it goes 'disconnected' then disable early-printk altogether in this case and trigger an emergency printk() so that there's chance that the user notices [if the system does not misbehave otherwise]. I.e. try to be as robust and informative as lockdep - yet don't lock up the host kernel: lockdep too is called from very deep internals, there are various conditions where it sees corrupt data structures (i.e. a 'disconnect' - a system environment outside the normal bounds of operation), yet of the kernel and over the last 10+ years of lockdep's existence we had very, very few cases of lockdep itself locking up and behaving unpredictably. Thanks, Ingo -- 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
