Transcript Linux Interrupt handling

Linux Interrupt Handling
PC style
Output
• Application sends data via driver
– Driver sends data to device
• If device can accept more data
– Device raises voltage on hardware line
• Interrupt Request Channels (IRQ’s)
• Limited in number
– Interrupt Service Routine (ISR) gets control, wakes
user Process
– Loop back to top
• End of processing
More on ISR’s
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# devices> # of IRQ’s
IRQ’s must be shared by multiple devices
Linux 2.4: chains of ISR’s
ISR’s might be long-running
Can’t afford to wait