Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750900AbWCBFDM (ORCPT ); Thu, 2 Mar 2006 00:03:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750902AbWCBFDM (ORCPT ); Thu, 2 Mar 2006 00:03:12 -0500 Received: from ns2.suse.de ([195.135.220.15]:38352 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1750866AbWCBFDM (ORCPT ); Thu, 2 Mar 2006 00:03:12 -0500 From: Andi Kleen To: Andrew Morton Subject: Re: [patch] i386: port ATI timer fix from x86_64 to i386 II Date: Thu, 2 Mar 2006 06:02:59 +0100 User-Agent: KMail/1.9.1 Cc: torvalds@osdl.org, linux-kernel@vger.kernel.org, Chuck Ebbert <76306.1226@compuserve.com> References: <200602281905_MC3-1-B97E-7FDC@compuserve.com> <20060301025219.2034924c.akpm@osdl.org> In-Reply-To: <20060301025219.2034924c.akpm@osdl.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200603020603.00210.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6071 Lines: 192 On Wednesday 01 March 2006 11:52, Andrew Morton wrote: > Well.. the patch had a flagrant won't-compile if CONFIG_X86_IO_APIC=y, so > I'd consider it a bit green. I did my own version of it then. Tested it a bit in various configurations and it works for me. I would consider it a 2.6.16 candidate because it fixes an important bug. Port the x86-64 ATI timer fix over to i386 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 interruopt 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: len.brown@intel.com Signed-off-by: Andi Kleen Index: linux/arch/i386/kernel/Makefile =================================================================== --- linux.orig/arch/i386/kernel/Makefile +++ linux/arch/i386/kernel/Makefile @@ -11,7 +11,7 @@ obj-y := process.o semaphore.o signal.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 Index: linux/arch/i386/kernel/acpi/Makefile =================================================================== --- linux.orig/arch/i386/kernel/acpi/Makefile +++ linux/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 Index: linux/arch/i386/kernel/acpi/earlyquirk.c =================================================================== --- linux.orig/arch/i386/kernel/acpi/earlyquirk.c +++ linux/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; } Index: linux/arch/i386/kernel/io_apic.c =================================================================== --- linux.orig/arch/i386/kernel/io_apic.c +++ linux/arch/i386/kernel/io_apic.c @@ -51,6 +51,8 @@ static struct { int pin, apic; } ioapic_ 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 Index: linux/include/asm-i386/apic.h =================================================================== --- linux.orig/include/asm-i386/apic.h +++ linux/include/asm-i386/apic.h @@ -137,6 +137,8 @@ void switch_APIC_timer_to_ipi(void *cpum 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) { } Index: linux/Documentation/i386/boot-options.txt =================================================================== --- /dev/null +++ linux/Documentation/i386/boot-options.txt @@ -0,0 +1,8 @@ + +Some i386 specific boot options + + 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. + + Index: linux/arch/i386/kernel/acpi/boot.c =================================================================== --- linux.orig/arch/i386/kernel/acpi/boot.c +++ linux/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); Index: linux/arch/i386/kernel/setup.c =================================================================== --- linux.orig/arch/i386/kernel/setup.c +++ linux/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. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/