Messages in this thread Patch in this message | | | Date | Sat, 2 Jun 2007 16:48:05 -0700 (PDT) | From | Tear <> | Subject | Re: [RFC][PATCH] IO-APIC blacklist |
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Linus Torvalds wrote: > On Sat, 2 Jun 2007, Tear wrote: > > > > > > Wouldn't this also disable the IOAPIC in the (working) ACPI+IOAPIC case? > > > > Yes, it would. However, I wanted to make my addition > > to the kernel generic so that other people with > > problematic IO-APIC implementations can blacklist > > their systems without checking whether ACPI is enabled > > or not. > > But that's just wrong. First off, all distro kernels come with ACPI on, so > the thing you're fixing is really just for somebody who compiles his own > kernel in a particular (and unusual/strange) configuration, and you're > making it _worse_ for everybody else.
Mr. Torvalds,
The patch scans the DMI for "Dell OptiPlex GX240" and disables IO-APIC only if such a system is detected. It does not disable IO-APIC for other people.
In addition, Dell OptiPlex GX240 is (at least currently) in the ACPI blacklist. So with a regular distro, one gets IO-APIC and acpi=ht which causes USB transfers to be very slow.
I have made an attempt to get Dell OptiPlex GX240 out of the ACPI blacklist. Please see: http://marc.info/?t=117897881900001&r=1&w=2
Nevertheless, I am willing to modify the patch to make IO-APIC work when ACPI is enabled. A quick search pointed me to the variable named "acpi_disabled". I can use this variable to detect whether ACPI is enabled and disable IO-APIC if it is not. Please see the attached patch for such an implementation.
> And you're blacklisting it without even understaning _what_ is wrong. I > really think we should figure that part out first,
I willing to put effort into figuring out what is wrong. Please let me know if there is anything I can do to further our information about this problem. As I said before, I would be glad to send to you the diff between any of the four cases I mentioned in my previous e-mail to you.
Were you able to take a look at the dmesg outputs in my previous e-mail?
Thank you for your attention.
Regards, - Tear
____________________________________________________________________________________ Choose the right car based on your needs. Check out Yahoo! Autos new Car Finder tool. http://autos.yahoo.com/carfinder/--- linux-2.6.21.3.orig/arch/i386/kernel/io_apic.c 2007-06-02 14:17:10.000000000 +0000 +++ linux-2.6.21.3/arch/i386/kernel/io_apic.c 2007-06-02 22:24:44.000000000 +0000 @@ -35,6 +35,7 @@ #include <linux/msi.h> #include <linux/htirq.h> #include <linux/freezer.h> +#include <linux/dmi.h> #include <asm/io.h> #include <asm/smp.h> @@ -44,6 +45,7 @@ #include <asm/nmi.h> #include <asm/msidef.h> #include <asm/hypertransport.h> +#include <asm/acpi.h> #include <mach_apic.h> #include <mach_apicdef.h> @@ -98,6 +100,33 @@ unsigned int data; }; +static int __init disable_gx240_ioapic(struct dmi_system_id *d) +{ + /* Disable IO-APIC only if ACPI is disabled */ + if (acpi_disabled) { + printk(KERN_WARNING "%s detected... Disabling IO-APIC\n", d->ident); + skip_ioapic_setup = 1; + } + return(0); +} + +static struct dmi_system_id __initdata ioapic_blacklist_dmi_table[] = { + { + .callback = disable_gx240_ioapic, + .ident = "Dell OptiPlex GX240", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex GX240"), + }, + }, + { } +}; + +void __init check_ioapic_blacklist(void) { + printk(KERN_INFO "Checking for IO-APIC blacklisted systems...\n"); + dmi_check_system(ioapic_blacklist_dmi_table); +} + static __attribute_const__ struct io_apic __iomem *io_apic_base(int idx) { return (void __iomem *) __fix_to_virt(FIX_IO_APIC_BASE_0 + idx) --- linux-2.6.21.3.orig/arch/i386/kernel/setup.c 2007-06-02 14:17:10.000000000 +0000 +++ linux-2.6.21.3/arch/i386/kernel/setup.c 2007-06-02 22:39:46.000000000 +0000 @@ -124,6 +124,7 @@ #endif extern void early_cpu_init(void); +extern void check_ioapic_blacklist(void); extern int root_mountflags; unsigned long saved_videomode; @@ -642,6 +643,11 @@ "CONFIG_X86_GENERICARCH or CONFIG_X86_BIGSMP.\n"); #endif #endif + +#ifdef CONFIG_X86_IO_APIC + check_ioapic_blacklist(); /* This must be after acpi_boot_init */ +#endif + #ifdef CONFIG_X86_LOCAL_APIC if (smp_found_config) get_smp_config(); | |