Bug 2495 - ACPI_BOOT should be disablable even if SMP is selected
Summary: ACPI_BOOT should be disablable even if SMP is selected
Status: CLOSED CODE_FIX
Alias: None
Product: ACPI
Classification: Unclassified
Component: Other (show other bugs)
Hardware: i386 Linux
: P2 normal
Assignee: Len Brown
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2004-04-11 15:50 UTC by Charles Duffy
Modified: 2005-10-17 13:11 UTC (History)
1 user (show)

See Also:
Kernel Version: 2.4.25, 2.6.4
Subsystem:
Regression: ---
Bisected commit-id:


Attachments
2.6.8.1 patch (30.76 KB, patch)
2004-08-25 10:30 UTC, Len Brown
Details | Diff

Description Charles Duffy 2004-04-11 15:50:48 UTC
Distribution: RHAS
Hardware Environment: Hitachi HA8000/70
Software Environment: kernel.org kernel
Problem Description:

This hardware oopses on boot (due to a DSDT bug) if ACPI_BOOT is selected -- but
ACPI_BOOT is forced to be enabled if SMP is on, even though the hardware works
fine in SMP mode with ACPI_BOOT forcably turned off (and direct PCI bus
configuration enabled).

The kernel configuration tool should provide the ability to turn ACPI_BOOT off
even on a SMP build.

Steps to reproduce:

Run "make menuconfig". Completely disable ACPI, enable SMP, select direct PCI
bus configuration, exit and save, examine .config, notice that CONFIG_ACPI_BOOT
is still enabled.
Comment 1 Shaohua 2004-04-12 00:27:46 UTC
CONFIG_ACPI_BOOT is not a bug if acpi is disabled, since we must support HT. 
for BIOS error, _BBN error can't cause system oops, since you disabled ACPI. 
can you attach your config file? In my test, select ACPI_BOOT will not call 
any acpi bus related functions. I wonder why your does. thanks.
Comment 2 Shaohua 2004-04-12 02:04:51 UTC
And for the BIOS error, could you please try the patch in Bug 1662. It should 
resolve your problem. thanks.
Comment 3 Charles Duffy 2004-04-13 09:15:40 UTC
I'll grant that selecting CONFIG_ACPI_BOOT when SMP is enabled is a Good Thing
by default (no doubt it wouldn't be in there if it weren't); the enhancement
request I'm making is for a user-selectable option to force CONFIG_ACPI_BOOT to
be disabled even when SMP is on, with appropriate help text warning the user
about how disabling this on systems with HT support is a Bad Idea unless they
really know what they're doing.

And yes, the patch in bug#1662 does fix the oops on boot. (Incidentally, I've
also put together a DSDT that boots correctly with all devices available).
Comment 4 Len Brown 2004-04-13 22:43:07 UTC
At one point I had CONFIG_ACPI=n delete all ACPI code from the kernel. 
People complained that HT no longer worked b/c they didn't know that 
HT depended on ACPI.  Marcelo mandated that HT should work even 
without CONFIG_ACPI or any explicit selection by the user in menuconfig. 
 
That is how CONFIG_ACPI_BOOT came to be; and 2.4 will not change. 
 
In 2.6, note that CONFIG_ACPI_BOOT doesn't depend on CONFIG_SMP, 
it depends on CONFIG_X86_HT.  Maybe we can make CONFIG_X86_HT 
selectable and that would address the need in 2.6? 
 
 
 
Comment 5 Charles Duffy 2004-04-14 08:58:52 UTC
> Maybe we can make CONFIG_X86_HT selectable
> and that would address the need in 2.6?

WORKSFORME.
Comment 6 Len Brown 2004-08-25 10:30:59 UTC
Created attachment 3565 [details]
2.6.8.1 patch

The necessary fix is included in this Kconfig cleanup patch.
let me know if you have any trouble with it.
Comment 7 Len Brown 2005-08-26 19:35:02 UTC
the latest ACPI patches removes CONFIG_ACPI_BOOT altogether:
http://ftp.kernel.org/pub/linux/kernel/people/lenb/acpi/patches/release/2.6.13/
Comment 8 Len Brown 2005-10-17 13:11:42 UTC
CONFIG_ACPI_BOOT is gone as of 2.6.14-rc1 -- closing.

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