On Wed, Jul 16, 2014 at 7:17 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: >> Various workarounds cover some of these cases, and we have some ugly >> hacks in ChromeOS to make things work. It would be nice if a userspace >> power management daemon could listen to the lid-close event, and then >> have a way to temporarily power off these devices, potentially through >> sysfs. > > Isn't it common for laptops to go into system suspend when the lid is > closed? It's common, but it does not cover all possible cases. As was mentioned by Dmitry, the user may dock his laptop, close his lid and use external display, keyboard, and mouse. In that case, the internal devices should be disabled or else they may send bogus input when the laptop's B panel couples with the touchpad, for example. Even in the case where system suspend happens, we don't want to depend on that state change to disable these devices. It may take some time before the system enters suspend, and in the meantime the input devices with the lid closed may inadvertently cancel suspend by generating a pm_wakeup_event(), which is not what we want. Other scenarios outside of lid close where such a feature would be helpful would be for transforming form-factors such as Yoga style laptops where the screen can fold back into tablet mode, and the C panel touchpad and keyboard should be disabled. -- Benson Leung Software Engineer, Chrom* OS bleung@xxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
