diff options
| -rw-r--r-- | Documentation/x86_64/boot-options.txt | 4 | ||||
| -rw-r--r-- | arch/x86_64/kernel/io_apic.c | 46 |
2 files changed, 33 insertions, 17 deletions
diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt index 153740f460a6..1921353259ae 100644 --- a/Documentation/x86_64/boot-options.txt +++ b/Documentation/x86_64/boot-options.txt @@ -52,6 +52,10 @@ APICs apicmaintimer. Useful when your PIT timer is totally broken. + disable_8254_timer / enable_8254_timer + Enable interrupt 0 timer routing over the 8254 in addition to over + the IO-APIC. The kernel tries to set a sensible default. + Early Console syntax: earlyprintk=vga diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c index ffab8a756664..ffed464e6b12 100644 --- a/arch/x86_64/kernel/io_apic.c +++ b/arch/x86_64/kernel/io_apic.c @@ -50,6 +50,8 @@ static int no_timer_check; int disable_timer_pin_1 __initdata; +int timer_over_8254 __initdata = 1; + /* Where if anywhere is the i8259 connect in external int mode */ static struct { int pin, apic; } ioapic_i8259 = { -1, -1 }; @@ -251,6 +253,20 @@ static int __init enable_ioapic_setup(char *str) __setup("noapic", disable_ioapic_setup); __setup("apic", enable_ioapic_setup); +static int __init setup_disable_8254_timer(char *s) +{ + timer_over_8254 = -1; + return 1; +} +static int __init setup_enable_8254_timer(char *s) +{ + timer_over_8254 = 2; + return 1; +} + +__setup("disable_8254_timer", setup_disable_8254_timer); +__setup("enable_8254_timer", setup_enable_8254_timer); + #include <asm/pci-direct.h> #include <linux/pci_ids.h> #include <linux/pci.h> @@ -309,27 +325,20 @@ void __init check_ioapic(void) #endif /* RED-PEN skip them on mptables too? */ return; + + /* This should be actually default, but + for 2.6.16 let's do it for ATI only where + it's really needed. */ case PCI_VENDOR_ID_ATI: - if (apic_runs_main_timer != 0) - break; -#ifdef CONFIG_ACPI - /* Don't do this for laptops right - right now because their timer - doesn't necessarily tick in C2/3 */ - if (acpi_fadt.revision >= 3 && - (acpi_fadt.plvl2_lat + acpi_fadt.plvl3_lat) < 1100) { - printk(KERN_INFO -"ATI board detected, but seems to be a laptop. Timer might be shakey, sorry\n"); - break; - } -#endif + if (timer_over_8254 == 1) { + timer_over_8254 = 0; printk(KERN_INFO - "ATI board detected. Using APIC/PM timer.\n"); - apic_runs_main_timer = 1; - nohpet = 1; + "ATI board detected. Disabling timer routing over 8254.\n"); + } return; } + /* No multi-function device? */ type = read_pci_config_byte(num,slot,func, PCI_HEADER_TYPE); @@ -1773,6 +1782,8 @@ static inline void unlock_ExtINT_logic(void) * a wide range of boards and BIOS bugs. Fortunately only the timer IRQ * is so screwy. Thanks to Brian Perkins for testing/hacking this beast * fanatically on his truly buggy board. + * + * FIXME: really need to revamp this for modern platforms only. */ static inline void check_timer(void) { @@ -1795,7 +1806,8 @@ static inline void check_timer(void) */ apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT); init_8259A(1); - enable_8259A_irq(0); + if (timer_over_8254 > 0) + enable_8259A_irq(0); pin1 = find_isa_irq_pin(0, mp_INT); apic1 = find_isa_irq_apic(0, mp_INT); |