Re: [PATCH 2/2] acpi: Disable IRQ 0 through I/O APIC for some HPsystems

From: Robert Hancock
Date: Thu Jul 03 2008 - 04:18:34 EST


Maciej W. Rozycki wrote:
From: Matthew Garrett <mjg59@xxxxxxxxxxxxx>

Some HP laptops have a problem with their DSDT reporting as
HP/SB400/10000, which includes some code which overrides all temperature
trip points to 16C if the INTIN2 input of the I/O APIC is enabled. This
input is incorrectly designated the ISA IRQ 0 via an interrupt source
override even though it is wired to the output of the master 8259A and
INTIN0 is not connected at all. So far two models have been identified, namely nx6125 and nx6325.

Use a knob provided by the I/O APIC interrupt registration code to
abandon any attempts to route IRQ 0 through the I/O APIC for these
systems.

Just a thought.. has anyone recently looked into using the RTC timer instead of the PIT as the default clockevent source? There still seem to be systems like these seeping through with broken PIT through IOAPIC since Windows apparently doesn't use that config at all. If we could use the RTC instead (which is apparently what Windows does) we could avoid that problem.

The last I read on the subject, the issue was that the RTC timer frequencies didn't match the existing Linux HZ values, but I'm not sure if that's still an issue with the current clockevents infrastructure..
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