diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 2 | ||||
| -rw-r--r-- | arch/i386/kernel/apic.c | 52 |
2 files changed, 54 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 856c8b114e71..06377c76e734 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1117,6 +1117,8 @@ and is between 256 and 4096 characters. It is defined in the file nolapic [IA-32,APIC] Do not enable or use the local APIC. + nolapic_timer [IA-32,APIC] Do not use the local APIC timer. + noltlbs [PPC] Do not use large page/tlb entries for kernel lowmem mapping on PPC40x. diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c index 5cff7970911e..36825117835d 100644 --- a/arch/i386/kernel/apic.c +++ b/arch/i386/kernel/apic.c @@ -28,6 +28,7 @@ #include <linux/clockchips.h> #include <linux/acpi_pmtmr.h> #include <linux/module.h> +#include <linux/dmi.h> #include <asm/atomic.h> #include <asm/smp.h> @@ -61,6 +62,8 @@ static int enable_local_apic __initdata = 0; /* Local APIC timer verification ok */ static int local_apic_timer_verify_ok; +/* Disable local APIC timer from the kernel commandline or via dmi quirk */ +static int local_apic_timer_disabled; /* * Debug level, exported for io_apic.c @@ -266,6 +269,32 @@ static void __devinit setup_APIC_timer(void) } /* + * Detect systems with known broken BIOS implementations + */ +static int __init lapic_check_broken_bios(struct dmi_system_id *d) +{ + printk(KERN_NOTICE "%s detected: disabling lapic timer.\n", + d->ident); + local_apic_timer_disabled = 1; + return 0; +} + +static struct dmi_system_id __initdata broken_bios_dmi_table[] = { + { + /* + * BIOS exports only C1 state, but uses deeper power + * modes behind the kernels back. + */ + .callback = lapic_check_broken_bios, + .ident = "HP nx6325", + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq nx6325"), + }, + }, + {} +}; + +/* * In this functions we calibrate APIC bus clocks to the external timer. * * We want to do the calibration only once since we want to have local timer @@ -340,6 +369,22 @@ void __init setup_boot_APIC_clock(void) long delta, deltapm; int pm_referenced = 0; + /* Detect know broken systems */ + dmi_check_system(broken_bios_dmi_table); + + /* + * The local apic timer can be disabled via the kernel + * commandline or from the dmi quirk above. Register the lapic + * timer as a dummy clock event source on SMP systems, so the + * broadcast mechanism is used. On UP systems simply ignore it. + */ + if (local_apic_timer_disabled) { + /* No broadcast on UP ! */ + if (num_possible_cpus() > 1) + setup_APIC_timer(); + return; + } + apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n" "calibrating APIC timer ...\n"); @@ -1179,6 +1224,13 @@ static int __init parse_nolapic(char *arg) } early_param("nolapic", parse_nolapic); +static int __init parse_disable_lapic_timer(char *arg) +{ + local_apic_timer_disabled = 1; + return 0; +} +early_param("nolapic_timer", parse_disable_lapic_timer); + static int __init apic_set_verbosity(char *str) { if (strcmp("debug", str) == 0) |