Reads from an HPET register require a round trip to the south bridge and are
almost as slow as PCI reads. By caching the last value we've written to the
comparator register, we can eliminate all HPET reads from the fast path in the
emulated RTC interrupt handler.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make sure that the RTC timer is in non-periodic mode; some stupid BIOS might
have initialized it to periodic mode.
Furthermore, don't set the SETVAL bit in the config register. This wouldn't
have any effect unless the timer was in period mode (which it isn't), and then
the actual timer frequency would be half that of the desired one because
incrementing the comparator in the interrupt handler would be done after the
hardware has already incremented it itself.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When the emulated RTC interrupt is no longer needed, we better disable it;
otherwise, we get a spurious interrupt whenever the timer has rolled over and
reaches the same comparator value.
Having a superfluous interrupt every five minutes doesn't hurt much, but it's
bad style anyway. ;-)
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Acked-by: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With hpet enabled, cpu hotplug uses some routines marked with __init.
Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently the i386 HPET code assumes the entire HPET implementation from
the spec is present. This breaks on boxes that do not implement the
optional legacy timer replacement functionality portion of the spec.
This patch, which is very similar to my x86-64 patch for the same issue,
fixes the problem allowing i386 systems that cannot use the HPET for the
timer interrupt and RTC to still use the HPET as a time source. I've
tested this patch on a system systems without HPET, with HPET but without
legacy timer replacement, as well as HPET with legacy timer replacement.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Clemens Ladisch
Shaohua Li
john stultz
Linus Torvalds