(Re-sending with correct mailing list addresses.) Hi, When the lid of a laptop is closed, certain devices can no longer provide interesting input or will even produce bogus input, such as: - input devices: touchscreen, touchpad, keyboard - sensors: ambient light sensor, accelerometer, magnetometer - a video camera mounted on the lid - display backlight 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. I've been discussing this with Dmitry and Benson (cc'd), and we've been wondering whether we could come up with a generic solution that could benefit multiple device classes. There's some overlap with runtime PM here. The action to be taken in such a situation would probably be similar to a runtime suspend. The match is not perfect though, since devices with more than two power states might want to enter different states depending on the situation. It's somewhat difficult to get the semantics right, since handles to such devices might still be open. It might be easier to implement behavior specific to device classes. On the other hand, it would be nice to have a uniform way of shutting devices down, and not introduce another possible path for a device to enter a power-saving state. Rafael, can you give us your opinion on this? Kind regards, Patrik -- 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
