My Opera
Misguided attempts on saving money and How Not To Do Things
Wednesday, November 9, 2011 6:06:21 AM
I finally found out how to control the Gdium's fan.
As the title suggests, it's quite bizarre. The temperature monitor chip they used is an LM75 which does exactly one thing - measure its own temperature and optionally notify the CPU if it gets too hot. On Gdium, this signal is abused to 'control' a fan. This approach has a few distinct disadvantages over using an actual fan controller:
I'm more and more getting the impression that whoever designed the Gdium didn't really think things through. First there is no CPU clock independent high reolution timer. Battery and temperature monitoring chips as well as some of the buttons have to be polled. And now the thing is loud by design.
Someone's been cutting the wrong corners.
As the title suggests, it's quite bizarre. The temperature monitor chip they used is an LM75 which does exactly one thing - measure its own temperature and optionally notify the CPU if it gets too hot. On Gdium, this signal is abused to 'control' a fan. This approach has a few distinct disadvantages over using an actual fan controller:
- No speed control. The thing is either loud or it doesn't spin.
- No fan monitoring. There is no way to check if the fan is actually spinning.
- Most fan controllers support at least one external sensor to be tacked on the CPU or whatever else gets especially hot ( usually the graphics chip ) in addition to an internal sensor. Gdium's CPU has no built-in sensor, and neither does the graphics chip.
I'm more and more getting the impression that whoever designed the Gdium didn't really think things through. First there is no CPU clock independent high reolution timer. Battery and temperature monitoring chips as well as some of the buttons have to be polled. And now the thing is loud by design.
Someone's been cutting the wrong corners.
