Messages in this thread | | | Date | Sun, 23 Jul 2006 11:30:01 -0700 | From | Andrew Morton <> | Subject | Re: Cross platform method for detecting hot unplug in irq handler |
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On Sun, 23 Jul 2006 14:11:01 +0100 James Courtier-Dutton <James@superbug.co.uk> wrote:
> Hi, > > 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?
Cardbus has detection pins, ad they can be queried via the controller. But it's too slow and afaik cardbus will reliably rern 0xffffffff for a removed card.
Lots of drivers treat a read of all-ones as indicating a removed card. It works. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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