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Date: Mon, 21 Apr 2008 13:12:41 +0200 From: "Frantisek Rysanek" <Frantisek.Rysanek@...t.cz> To: linux-kernel@...r.kernel.org Subject: What pokes the ISA IO port of 0x211 ? Dear Everyone, I'm dealing with an embedded PC motherboard that contains some custom circuitry (GPIO), accessible via an ISA IO range between 0x200 and 0x218. There's an interesting issue with this in recent Linux (tried 2.6.22.6 and 2.6.24.2): something probes IO port 0x211 on boot, which happens to be an add-on buzzer control port - effectively the kernel boot launches an accoustic alarm :-) Any ideas what this could be? Obviously it's no problem for me to write a tiny kernel module to disable the alarm again, and I've actually verified the problem using ioperm()+outb() from user space, but still I'd be interested to know which particular piece of code could be probing that address... The address decode might be implemented using some general-purpose features of the Winbond W83627HF SuperIO (as there's no ISA in the system, just ICH4 LPC) - but it seems quite unlikely that this would be caused by something fiddling with the W83627 config registers. It really seems like something writes 0xFF to IO port 0x211. Thanks for your time and attention :-) Frank Rysanek -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.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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