linux/arch/i386
Thomas Gleixner 6b3964cde7 [PATCH] i386: clockevents fix breakage on Geode/Cyrix PIT implementations
The PIT has no dedicated mode for shut down. The only way to disable PIT
is to put it into one shot mode. AMD implementations of PIT on Geode
(also observed on Cyrix) are confused by an "empty" transition from
CLOCK_EVT_MODE_UNUSED to CLOCK_EVT_MODE_SHUTDOWN, which puts the PIT
into one shot mode momentarily.

I realized after staring helpless at the bug report
http://bugzilla.kernel.org/show_bug.cgi?id=8027 for quite a while, that
the only change, which might influence the bogomips calibration, is the
above transition during the PIT initialization.

Avoiding the unnecessary switch to oneshot and later to periodic mode
fixes the weird bogomips value and also the resulting slowness.

The fix is confirmed on OLPC and another Geode based box.

Note: this is unrelated to the Dual Core problem discussed here:
http://lkml.org/lkml/2007/3/17/48

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-22 19:33:30 -07:00
..
boot Use ARRAY_SIZE() macro in i386 relocs.c file 2007-02-17 19:10:01 +01:00
crypto [CRYPTO] api: Get rid of flags argument to setkey 2006-09-21 11:41:02 +10:00
kernel [PATCH] i386: clockevents fix breakage on Geode/Cyrix PIT implementations 2007-03-22 19:33:30 -07:00
lib {rd,wr}msr_on_cpu SMP=n optimization 2007-02-20 14:29:37 -05:00
mach-default [PATCH] clockevents: i386 drivers 2007-02-16 08:13:59 -08:00
mach-es7000 ACPICA: Remove duplicate table manager 2007-02-02 21:14:28 -05:00
mach-generic [PATCH] i386: make apic probe function non-init 2007-01-11 01:52:44 +01:00
mach-visws [PATCH] visws: sgivwfb as module needs exports 2006-12-08 08:29:07 -08:00
mach-voyager [PATCH] x86: fix PDA variables to work during boot 2007-01-22 19:39:36 -08:00
math-emu [PATCH] i386: avoid gcc extension 2007-02-13 13:26:24 +01:00
mm [PATCH] i386: Remove extern declaration from mm/discontig.c, put in header. 2007-02-13 13:26:26 +01:00
oprofile Replace remaining references to "driverfs" with "sysfs". 2007-02-17 19:13:42 +01:00
pci PCI: add systems for automatic breadth-first device sorting 2007-02-16 15:30:11 -08:00
power Merge branch 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6 2006-12-07 08:59:11 -08:00
defconfig [PATCH] i386: Update defconfig 2007-03-16 21:07:36 +01:00
Kconfig [PATCH] Fix VMI and COMPAT_VDSO for 2.6.21 2007-03-12 16:33:51 -07:00
Kconfig.cpu [PATCH] i386: Remove unused kernel config option X86_XADD 2007-02-13 13:26:25 +01:00
Kconfig.debug [PATCH] i386: Paravirt debug defaults off 2007-02-13 13:26:22 +01:00
Makefile [PATCH] x86: add -freg-struct-return to CFLAGS 2007-02-26 12:53:30 -08:00
Makefile.cpu [PATCH] i386: Add support for compilation for Core2 2006-12-07 02:14:09 +01:00