From: Andi Kleen Date: Thu, 9 Mar 2006 01:57:25 +0000 (-0800) Subject: [PATCH] i386: port ATI timer fix from x86_64 to i386 II X-Git-Tag: v2.6.16-rc6~56 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f9262c12c0084ddba445a9a42e98994018e51400;p=linux-2.6 [PATCH] i386: port ATI timer fix from x86_64 to i386 II ATI chipsets tend to generate double timer interrupts for the local APIC timer when both the 8254 and the IO-APIC timer pins are enabled. This is because they route it to both and the result is anded together and the CPU ends up processing it twice. This patch changes check_timer to disable the 8254 routing for interrupt 0. I think it would be safe on all chipsets actually (i tested it on a couple and it worked everywhere) and Windows seems to do it in a similar way, but to be conservative this patch only enables this mode on ATI (and adds options to enable/disable too) Ported over from a similar x86-64 change. I reused the ACPI earlyquirk infrastructure for the ATI bridge check, but tweaked it a bit to work even without ACPI. Inspired by a patch from Chuck Ebbert, but redone. Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: "Brown, Len" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index bad5987c47..fc99075e0a 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -335,6 +335,12 @@ running once the system is up. timesource is not avalible, it defaults to PIT. Format: { pit | tsc | cyclone | pmtmr } + disable_8254_timer + enable_8254_timer + [IA32/X86_64] Disable/Enable interrupt 0 timer routing + over the 8254 in addition to over the IO-APIC. The + kernel tries to set a sensible default. + hpet= [IA-32,HPET] option to disable HPET and use PIT. Format: disable diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile index 53bb9a79e2..65656c033d 100644 --- a/arch/i386/kernel/Makefile +++ b/arch/i386/kernel/Makefile @@ -11,7 +11,7 @@ obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o \ obj-y += cpu/ obj-y += timers/ -obj-$(CONFIG_ACPI) += acpi/ +obj-y += acpi/ obj-$(CONFIG_X86_BIOS_REBOOT) += reboot.o obj-$(CONFIG_MCA) += mca.o obj-$(CONFIG_X86_MSR) += msr.o diff --git a/arch/i386/kernel/acpi/Makefile b/arch/i386/kernel/acpi/Makefile index d51c7313ca..7e9ac99354 100644 --- a/arch/i386/kernel/acpi/Makefile +++ b/arch/i386/kernel/acpi/Makefile @@ -1,4 +1,4 @@ -obj-y := boot.o +obj-$(CONFIG_ACPI) += boot.o obj-$(CONFIG_X86_IO_APIC) += earlyquirk.o obj-$(CONFIG_ACPI_SLEEP) += sleep.o wakeup.o diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c index 79577f0ace..f1a2194596 100644 --- a/arch/i386/kernel/acpi/boot.c +++ b/arch/i386/kernel/acpi/boot.c @@ -1111,9 +1111,6 @@ int __init acpi_boot_table_init(void) disable_acpi(); return error; } -#ifdef __i386__ - check_acpi_pci(); -#endif acpi_table_parse(ACPI_BOOT, acpi_parse_sbf); diff --git a/arch/i386/kernel/acpi/earlyquirk.c b/arch/i386/kernel/acpi/earlyquirk.c index f1b9d2a46d..2e3b643a4d 100644 --- a/arch/i386/kernel/acpi/earlyquirk.c +++ b/arch/i386/kernel/acpi/earlyquirk.c @@ -7,14 +7,22 @@ #include #include #include +#include static int __init check_bridge(int vendor, int device) { +#ifdef CONFIG_ACPI /* According to Nvidia all timer overrides are bogus. Just ignore them all. */ if (vendor == PCI_VENDOR_ID_NVIDIA) { acpi_skip_timer_override = 1; } +#endif + if (vendor == PCI_VENDOR_ID_ATI && timer_over_8254 == 1) { + timer_over_8254 = 0; + printk(KERN_INFO "ATI board detected. Disabling timer routing " + "over 8254.\n"); + } return 0; } diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c index 235822b3f4..39d9a5fa90 100644 --- a/arch/i386/kernel/io_apic.c +++ b/arch/i386/kernel/io_apic.c @@ -51,6 +51,8 @@ static struct { int pin, apic; } ioapic_i8259 = { -1, -1 }; static DEFINE_SPINLOCK(ioapic_lock); +int timer_over_8254 __initdata = 1; + /* * Is the SiS APIC rmw bug present ? * -1 = don't know, 0 = no, 1 = yes @@ -2267,7 +2269,8 @@ static inline void check_timer(void) apic_write_around(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT); init_8259A(1); timer_ack = 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); @@ -2392,6 +2395,20 @@ void __init setup_IO_APIC(void) print_IO_APIC(); } +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); + /* * Called after all the initialization is done. If we didnt find any * APIC bugs then we can allow the modify fast path diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c index 51e513b4f7..ab62a9f470 100644 --- a/arch/i386/kernel/setup.c +++ b/arch/i386/kernel/setup.c @@ -1599,6 +1599,10 @@ void __init setup_arch(char **cmdline_p) if (efi_enabled) efi_map_memmap(); +#ifdef CONFIG_X86_IO_APIC + check_acpi_pci(); /* Checks more than just ACPI actually */ +#endif + #ifdef CONFIG_ACPI /* * Parse the ACPI tables for possible boot-time SMP configuration. diff --git a/include/asm-i386/apic.h b/include/asm-i386/apic.h index d30b857157..ff9ac8d19e 100644 --- a/include/asm-i386/apic.h +++ b/include/asm-i386/apic.h @@ -137,6 +137,8 @@ void switch_APIC_timer_to_ipi(void *cpumask); void switch_ipi_to_APIC_timer(void *cpumask); #define ARCH_APICTIMER_STOPS_ON_C3 1 +extern int timer_over_8254; + #else /* !CONFIG_X86_LOCAL_APIC */ static inline void lapic_shutdown(void) { }