Re: [PATCH] x86: update_mptable need pci_routeirq

[Yinghai Lu <yinghai@kernel.org>]

Bjorn Helgaas wrote:
> On Friday 15 May 2009 03:13:20 pm Yinghai Lu wrote:
>> Bjorn Helgaas wrote:
>>> On Friday 15 May 2009 01:51:56 pm Yinghai Lu wrote:
>>>> to get all device irq routing and save them
>>> This changelog isn't really enough for me to understand
>>> what's going on.
>>>
>>>> Index: linux-2.6/arch/x86/kernel/mpparse.c
>>>> ===================================================================
>>>> --- linux-2.6.orig/arch/x86/kernel/mpparse.c
>>>> +++ linux-2.6/arch/x86/kernel/mpparse.c
>>>> @@ -17,6 +17,7 @@
>>>>  #include <linux/acpi.h>
>>>>  #include <linux/module.h>
>>>>  #include <linux/smp.h>
>>>> +#include <linux/pci.h>
>>>>  
>>>>  #include <asm/mtrr.h>
>>>>  #include <asm/mpspec.h>
>>>> @@ -961,6 +962,7 @@ static int __initdata enable_update_mpta
>>>>  static int __init update_mptable_setup(char *str)
>>>>  {
>>>>  	enable_update_mptable = 1;
>>>> +	pci_routeirq = 1;
>>> I hate to see new uses of pci_routeirq.  It'd be nice to remove it
>>> completely someday.  But maybe it can't be helped.
>>>
>>>>  	return 0;
>>>>  }
>>>>  early_param("update_mptable", update_mptable_setup);
>>> "update_mptable" is apparently a boot option, but it's not mentioned
>>> in Documentation/kernel-parameters.txt.  Is this some sort of debug
>>> code or BIOS-writer's helper?  Same with "alloc_mptable".  Why do
>>> we have this stuff?
>>>
>> 1. kexec path: after acpi kernel and use kexec to load kerenl with mptable support only or acpi=off
>> 2. help to BIOS engineer to understand how to set mptable and irq routing setup by chipset.
>>    esp system have several cards and there is bridge in those cards.
> 
> I was sort of hoping for a Documentation/kernel-parameters.txt patch.

current we have half commited in mainline.
missed the calling in drivers/acpi

and we are trying to move the calling to arch/x86/kernel/acpi/boot.c
hope Len will buy it.


> 
> Is (1) common enough to worry about?  What OSes don't have ACPI
> support?  What advantage is there to using "acpi=off"?

some other "OS" still use half ACPI tables... MADT etc. but still use mptable for irq routing.

some one want to disable acpi, because acpid is using 100%...

> 
> (2) sounds like something that should be under a config option, if
> it's in the mainline kernel at all.

sure, will make it as one CONFIG option that depends on ACPI.

Thanks

YH