Hacker News Reader

Comment by bradleyland | Hacker News Reader

Interesting. In the past, an external mouse (BT or USB) was required in order for a MacBook to operate in "clamshell mode". If no such device were connected, you couldn't get the laptop to turn on. Period. This makes me wonder if there isn't a firmware bug?

EDIT: An additional requirement (forgot): an external display must be attached. I'm doing some testing with my 2011 MacBook Air that is still running Lion.

CORRECTION: My MacBook Air is running Lion, not Snow Leopard. Brain fart!

View on HN

Seems like a more likely explanation is a hysteresis issue with the hardware lid sensor. It "opens" under vibration and allows the transient key events to be seen by whatever controller (my guess is that all this is preboot, so the CPU firmware isn't invoked) is listening for the wakeup events.

Basically, if the key sensors can be jiggled closed, the lid sensor can be jiggled open. And because these happen for the same reason at the same time, that's not a two-point failure mode; it's something you'd expect to happen.

I think that's probably the most plausible explanation. It makes me wonder what kind of g-forces the laptop is encountering. Most electronics aren't intended for "rugged" environments, and "ruggedized" equipment is a lot more expensive.

Honestly, I think this is a situation where Apple hardware is fragile instead of simply "not ruggedized". Traditionally laptops had hinge locks, for example, but the industry moved away from that because the unlocked hinges were perceived as nicer. Apple has always driven this process more than any other manufacturer. It's probably that they simply got burned here and chose a set of sensor/key/hinge designs that were a little too aggressively "thin".

I did some very detailed testing. I cannot wake my MacBook Air with the keyboard, regardless of condition.

https://gist.github.com/3699744

That's a lot of work!

I had issues with Snow Leopard where it wouldn't actually go to sleep. The screen shut down, but the power led stayed on, and it would drain the battery as if in use. This could be something similar.

Yeah, as I started, ideas kept coming and the test kept expanding. It was a cool exercise though. I feel like doing this kind of thing, while a waste of time, is good practice. It's helpful to go through the motions of detailed testing and reporting on simple little tasks like this, because those skills translate directly to more complex tasks.

This happened to me with my older MacBook Pro. On that model, the magnet next to the latch would loosen, causing the laptop to power up in my bag on the train or bus. I wouldn't notice this until I picked up the bag and noticed that it was very hot.

OMG! How did you manage to install Snow Leopard on Macbook Air 2012!? I'm very curious to know the method.

If you still have the DVD then I guess you can just pop it in your super drive.

Snow Leopard doesn't have the drivers for new hardware.

And MBA's don't have super drives!

http://www.amazon.com/Apple-Macbook-Air-Superdrive-MC684ZM/d...

Brain fart. Lion, not Snow Leopard. Time flies!

Reply on news.ycombinator.com