Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH] x86-64: Disable local APIC timer use on AMD systems with C1E | Date | Tue, 25 Sep 2007 22:55:04 +0200 |
| |
On Tuesday, 25 September 2007 21:37, Thomas Gleixner wrote: > commit 3556ddfa9284a86a59a9b78fe5894430f6ab4eef titled > > [PATCH] x86-64: Disable local APIC timer use on AMD systems with C1E > > solves a problem with AMD dual core laptops e.g. HP nx6325 (Turion 64 > X2) with C1E enabled: > > When both cores go into idle at the same time, then the system switches > into C1E state, which is basically the same as C3. This stops the local > apic timer. > > This was debugged right after the dyntick merge on i386 and despite the > patch title it fixes only the 32 bit path. > > x86_64 is still missing this fix. It seems that mainline is not really > affected by this issue, as the PIT is running and keeps jiffies > incrementing, but that's just waiting for trouble. > > -mm suffers from this problem due to the x86_64 high resolution timer > patches. > > This is a quick and dirty port of the i386 code to x86_64. > > I spent quite a time with Rafael to debug the -mm / hrt wreckage until > someone pointed us to this. I really had forgotten that we debugged this > half a year ago already. > > Sigh, is it just me or is there something yelling arch/x86 into my ear? > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
I have reworked the patch a bit so that it applies on top of 2.6.23-rc8-mm1 and compiles (my version is attached).
With this patch applied, the kernel boots correctly on the nx6325.
Greetings, Rafael
--- arch/x86_64/kernel/apic.c | 2 +- arch/x86_64/kernel/setup.c | 34 ++++++++++++++++++++++++++++++++++ include/asm-x86_64/apic.h | 1 + 3 files changed, 36 insertions(+), 1 deletion(-)
Index: linux-2.6.23-rc8-mm1/arch/x86_64/kernel/setup.c =================================================================== --- linux-2.6.23-rc8-mm1.orig/arch/x86_64/kernel/setup.c +++ linux-2.6.23-rc8-mm1/arch/x86_64/kernel/setup.c @@ -620,6 +620,37 @@ static void __cpuinit early_init_amd(str #endif } +#define ENABLE_C1E_MASK 0x18000000 +#define CPUID_PROCESSOR_SIGNATURE 1 +#define CPUID_XFAM 0x0ff00000 +#define CPUID_XFAM_K8 0x00000000 +#define CPUID_XFAM_10H 0x00100000 +#define CPUID_XFAM_11H 0x00200000 +#define CPUID_XMOD 0x000f0000 +#define CPUID_XMOD_REV_F 0x00040000 + +/* AMD systems with C1E don't have a working lAPIC timer. Check for that. */ +static __cpuinit int amd_apic_timer_broken(void) +{ + u32 lo, hi; + u32 eax = cpuid_eax(CPUID_PROCESSOR_SIGNATURE); + switch (eax & CPUID_XFAM) { + case CPUID_XFAM_K8: + if ((eax & CPUID_XMOD) < CPUID_XMOD_REV_F) + break; + case CPUID_XFAM_10H: + case CPUID_XFAM_11H: + rdmsr(MSR_K8_ENABLE_C1E, lo, hi); + if (lo & ENABLE_C1E_MASK) + return 1; + break; + default: + /* err on the side of caution */ + return 1; + } + return 0; +} + static void __cpuinit init_amd(struct cpuinfo_x86 *c) { unsigned level, flags, dummy; @@ -692,6 +723,9 @@ static void __cpuinit init_amd(struct cp if (c->x86 == 0x10 && !force_mwait) clear_bit(X86_FEATURE_MWAIT, &c->x86_capability); + if (amd_apic_timer_broken()) + disable_apic_timer = 1; + if (c->x86 >= 0xf && c->x86 <= 0x11 && !rdmsr_safe(MSR_VM_CR, &flags, &dummy) && (flags & 0x18)) Index: linux-2.6.23-rc8-mm1/include/asm-x86_64/apic.h =================================================================== --- linux-2.6.23-rc8-mm1.orig/include/asm-x86_64/apic.h +++ linux-2.6.23-rc8-mm1/include/asm-x86_64/apic.h @@ -19,6 +19,7 @@ extern int apic_verbosity; extern int apic_runs_main_timer; extern int ioapic_force; +extern int disable_apic_timer; /* * Define the default level of output to be very little Index: linux-2.6.23-rc8-mm1/arch/x86_64/kernel/apic.c =================================================================== --- linux-2.6.23-rc8-mm1.orig/arch/x86_64/kernel/apic.c +++ linux-2.6.23-rc8-mm1/arch/x86_64/kernel/apic.c @@ -41,8 +41,8 @@ #include <asm/apic.h> int apic_verbosity; +int disable_apic_timer __initdata; static int apic_calibrate_pmtmr __initdata; -static int disable_apic_timer __initdata; /* Local APIC timer works in C2? */ int local_apic_timer_c2_ok; | |