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author | David S. Miller <davem@davemloft.net> | 2008-06-10 09:22:26 (GMT) |
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committer | David S. Miller <davem@davemloft.net> | 2008-06-10 09:22:26 (GMT) |
commit | 65b53e4cc90e59936733b3b95b9451d2ca47528d (patch) | |
tree | 29932718192962671c48c3fd1ea017a6112459e8 /arch/x86/kernel/process.c | |
parent | 788c0a53164c05c5ccdb1472474372b72ba74644 (diff) | |
parent | 2e761e0532a784816e7e822dbaaece8c5d4be14d (diff) | |
download | linux-fsl-qoriq-65b53e4cc90e59936733b3b95b9451d2ca47528d.tar.xz |
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
drivers/net/tg3.c
drivers/net/wireless/rt2x00/rt2x00dev.c
net/mac80211/ieee80211_i.h
Diffstat (limited to 'arch/x86/kernel/process.c')
-rw-r--r-- | arch/x86/kernel/process.c | 36 |
1 files changed, 27 insertions, 9 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 67e9b4a..ba370dc 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -99,15 +99,6 @@ static void mwait_idle(void) local_irq_enable(); } - -static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c) -{ - if (force_mwait) - return 1; - /* Any C1 states supported? */ - return c->cpuid_level >= 5 && ((cpuid_edx(5) >> 4) & 0xf) > 0; -} - /* * On SMP it's slightly faster (but much more power-consuming!) * to poll the ->work.need_resched flag instead of waiting for the @@ -119,6 +110,33 @@ static void poll_idle(void) cpu_relax(); } +/* + * mwait selection logic: + * + * It depends on the CPU. For AMD CPUs that support MWAIT this is + * wrong. Family 0x10 and 0x11 CPUs will enter C1 on HLT. Powersavings + * then depend on a clock divisor and current Pstate of the core. If + * all cores of a processor are in halt state (C1) the processor can + * enter the C1E (C1 enhanced) state. If mwait is used this will never + * happen. + * + * idle=mwait overrides this decision and forces the usage of mwait. + */ +static int __cpuinit mwait_usable(const struct cpuinfo_x86 *c) +{ + if (force_mwait) + return 1; + + if (c->x86_vendor == X86_VENDOR_AMD) { + switch(c->x86) { + case 0x10: + case 0x11: + return 0; + } + } + return 1; +} + void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) { static int selected; |