Re: RTC Chip and IRQ8 on 2.6.9

From: linux-os
Date: Sun Nov 14 2004 - 09:30:40 EST

On Sun, 14 Nov 2004, Florian Schmidt wrote:

On Fri, 12 Nov 2004 11:47:10 -0500 (EST)
linux-os <linux-os@xxxxxxxxxxxxxxxxxx> wrote:

I must use the RTC and IRQ8 in a driver being ported from
2.4.20 to 2.6.9. When I attempt request_irq(8,...), it
returns -EBUSY. I have disabled everything in .config
that has "RTC" in it.

The RTC interrupt is used to precisely time the sequencing
of a precision A/D converter. It is mandatory that I use
it because the precise interval is essential for its
IIR filter that produces 20 bits of resolution from a
16 bit A/D.

8: 1 IO-APIC-edge rtc

maybe it's the HPET timer providing rtc emulation?


It turned out to be RTC timer software that, when built-in,
grabbed IRQ8 even though it didn't use it. I reconfigured
it as a module. Then, when I unload the module, the IRQ gets
freed up. (Fedora loads, I guess, everything...).

Dick Johnson
Penguin : Linux version 2.6.9 on an i686 machine (5537.79 BogoMips).
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