Timer interrupt lost on some x86_64 systems

Vivek Goyal vgoyal at in.ibm.com
Tue Nov 13 02:31:28 EST 2007

On Mon, Nov 12, 2007 at 10:41:19AM -0500, Neil Horman wrote:
> Although, as I look at it, it would appear that time_init from start_kernel does
> seem to init the hpet if its available, and it silently fails if that doesn't
> work, moving on to the pmtimer and pit.  I wonder if there is some extra magic
> to resetting the hpet to run on a different cpu for some systems...
> Neil

Any idea what kind of timer devices this motherborad has got? Which timer
device gets activated in first kernel? Then we can focus on why the
interrupts from same device are not coming in second kernel.

In the past I have found issues with interrupt routing on IOPAPIC and
interrupt lockup on LAPIC. But these issues are already solved. I would
also think of priting LAPIC and IOAPIC entries to see how timer interrupt
routing changes from first kernel to second.


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