How are alarms triggered?
It is possible to monitor each sensor and have an alarm go off if it crosses some pre-determined limits. There are two sorts of interrupts which can be generated by sensor chips if this happens (it depends a bit on the actual chip if both are supported; the LM80, for example, has only IRQ interrupts): IRQ interrupts and SMI interrupts. IRQ stands for Interrupt Request and are the interrupt lines you can find in /proc/interrupts. SMI stands for System Management Interrupt, and is a special interrupt which puts the processor in a secure environment independent of any other things running. SMI is currently not supported by the Linux kernel. IRQs are supported, of course. Even if no interrupt is generated, some bits in a status register will be set until the register is read the next time. If the alarm condition persists after that, the bits will be set on the next scanning sweep, etc. Most drivers in our package do not support interrupts at this time.
It is possible to monitor each sensor and have an alarm go off if it crosses some pre-determined limits. There are two sorts of interrupts which can be generated by sensor chips if this happens (it depends a bit on the actual chip if both are supported; the LM80, for example, has only IRQ interrupts): IRQ interrupts and SMI interrupts.
