Messages in this thread |  | | | Date | Mon, 3 Mar 1997 21:18:54 -0500 (EST) | | From | "Richard B. Johnson" <> | | Subject | Re: IRQs |
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On Mon, 3 Mar 1997, Bob Welsh wrote:
> Hi, > Quick question. Is it possible to selectively disable interrupts for a given > IRQ in 386 architecture or can one only disable all interrupts. We are > working on a device driver for a rather stupid device. As we are waiting for > a register to clear on the device, it appears the device is interrupting and a > new device command from the interrupt routine is reseting the register. > Unfortunately disabling interrupts on the device also clears the register. > Any suggestions? > > Bob Welsh > Shure can. The control port for the "low" IRQs is at 0x21 and the "high" IRQs is at 0xA1. It is a bit-mapped mask, bit 0 is IRQ0 on the low port. Bit 0 is IRQ8 on the high port (the interrupt controllers are cascaded).. These ports are R/W, you can save the bits then put them back the way they were.
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