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Revision 37873241


Added by aliguori over 12 years ago

hpet: Fix emulation of HPET_TN_SETVAL (Jan Kiszka)

While Intel's spec is not that clear here, latest changes to Linux' HPET
code (commit c23e253e67c9d8a91a0ffa33c1f571a17f0a2403, "x86: hpet: stop
HPET_COUNTER when programming periodic mode") strongly suggest that
HPET_TN_SETVAL rather means: Set both the comparator value and

With this patch applied, I'm again able to boot 2.6.30-rc kernels as
they no longer panic like this (which was due to the comparator
register remaining 0):

..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
..MP-BIOS bug: 8254 timer not connected to IO-APIC
...trying to set up timer (IRQ0) through the 8259A ...
..... (found apic 0 pin 2) ...
....... failed.
...trying to set up timer as Virtual Wire IRQ...
..... failed.
...trying to set up timer as ExtINT IRQ...
..... failed :(.
Kernel panic - not syncing: IO-APIC + timer doesn't work! [...]

Signed-off-by: Jan Kiszka <>
Signed-off-by: Anthony Liguori <>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7168 c046a42c-6fe2-441c-8c8c-71466251a162


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