From: Ingo Molnar <mingo@elte.hu>
To: Andi Kleen <ak@suse.de>
Cc: andreas.herrmann3@amd.com, linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] [11/20] x86: Use the correct cpuid method to detect MWAIT support for C states
Date: Thu, 3 Jan 2008 11:45:26 +0100 [thread overview]
Message-ID: <20080103104526.GC29194@elte.hu> (raw)
In-Reply-To: <20080103005006.BE79A14D40@wotan.suse.de>
* Andi Kleen <ak@suse.de> wrote:
> +static int 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;
> +}
> +
> void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
> {
> - if (cpu_has(c, X86_FEATURE_MWAIT)) {
> + if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
> printk("monitor/mwait feature present.\n");
hm, why not clear FEATURE_MWAIT if it's "not usable"? That's the
standard approach we do for CPU features that do not work.
Ingo
next prev parent reply other threads:[~2008-01-03 10:45 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-03 0:49 [PATCH] [1/20] x86: Make ptrace.h safe to include from assembler code Andi Kleen
2008-01-03 0:49 ` [PATCH] [2/20] x86: Implement support to synchronize RDTSC through MFENCE on AMD CPUs Andi Kleen
2008-01-03 0:49 ` [PATCH] [3/20] x86: Implement support to synchronize RDTSC with LFENCE on Intel CPUs Andi Kleen
2008-01-03 0:49 ` [PATCH] [4/20] x86: Move nop declarations into separate include file Andi Kleen
2008-01-03 0:50 ` [PATCH] [5/20] x86: Introduce nsec_barrier() Andi Kleen
2008-01-03 10:47 ` Ingo Molnar
2008-01-03 12:55 ` Andi Kleen
2008-01-07 20:01 ` [PATCH] [5/20] x86: Introduce nsec_barrier() II Andi Kleen
2008-01-03 0:50 ` [PATCH] [6/20] x86: Remove get_cycles_sync Andi Kleen
2008-01-03 0:50 ` [PATCH] [7/20] x86: Remove the now unused X86_FEATURE_SYNC_RDTSC Andi Kleen
2008-01-03 0:50 ` [PATCH] [8/20] x86: Make TIF_MCE_NOTIFY optional Andi Kleen
2008-01-03 0:50 ` [PATCH] [9/20] x86: Don't use oops_begin in 64bit mce code Andi Kleen
2008-01-03 10:39 ` Ingo Molnar
2008-01-03 12:52 ` Andi Kleen
2008-01-03 0:50 ` [PATCH] [10/20] i386: Move MWAIT idle check to generic CPU initialization Andi Kleen
2008-01-03 10:42 ` Ingo Molnar
2008-01-03 0:50 ` [PATCH] [11/20] x86: Use the correct cpuid method to detect MWAIT support for C states Andi Kleen
2008-01-03 10:45 ` Ingo Molnar [this message]
2008-01-03 12:53 ` Andi Kleen
2008-01-03 0:50 ` [PATCH] [12/20] x86: Use a per cpu timer for correctable machine check checking Andi Kleen
2008-01-03 10:49 ` Ingo Molnar
2008-01-03 12:56 ` Andi Kleen
2008-01-03 0:50 ` [PATCH] [13/20] x86: Use a deferrable timer for the correctable machine check poller Andi Kleen
2008-01-03 0:50 ` [PATCH] [14/20] x86: Add per cpu counters for machine check polls / machine check events Andi Kleen
2008-01-03 0:50 ` [PATCH] [15/20] x86: Move X86_FEATURE_CONSTANT_TSC into early cpu feature detection Andi Kleen
2008-01-03 11:03 ` Ingo Molnar
2008-01-03 0:50 ` [PATCH] [16/20] x86: Allow TSC clock source on AMD Fam10h and some cleanup Andi Kleen
2008-01-04 8:38 ` Ingo Molnar
2008-01-03 0:50 ` [PATCH] [17/20] x86: Remove explicit C3 TSC check on 64bit Andi Kleen
2008-01-04 8:38 ` Ingo Molnar
2008-01-03 0:50 ` [PATCH] [18/20] x86: Don't disable TSC in any C states on AMD Fam10h Andi Kleen
2008-01-04 8:40 ` Ingo Molnar
2008-01-03 0:50 ` [PATCH] [19/20] x86: Use shorter addresses in i386 segfault printks Andi Kleen
2008-01-03 10:56 ` Ingo Molnar
2008-01-03 12:56 ` Andi Kleen
2008-01-03 0:50 ` [PATCH] [20/20] x86: Print which shared library/executable faulted in segfault etc. messages Andi Kleen
2008-01-03 6:28 ` Eric Dumazet
2008-01-03 11:00 ` Ingo Molnar
2008-01-03 13:06 ` Andi Kleen
2008-01-03 9:54 ` [PATCH] [1/20] x86: Make ptrace.h safe to include from assembler code Ingo Molnar
2008-01-03 12:57 ` Andi Kleen
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