Cross platform method for detecting hot unplug in irq handler

From: James Courtier-Dutton
Date: Sun Jul 23 2006 - 09:10:02 EST


I am writing a driver for a PCMCIA device.
When the card is removed, the driver's IRQ handler is called.
The first thing the IRQ handler does is read a status register from the
card's IOPORT. On the ia32 (i386) platform, the resulting status read
will return 0xffffffff. If the driver reads this value, it assumes the
card has been removed and acts accordingly.

Is this a reliable way of detecting PCMCIA or Hotplug card removal
inside an IRQ handler?
Is it consistent cross platforms. E.g. ia64, amd64, PPC, MIPS etc.?
Does a more reliable detection method exist in the kernel?

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