[Bug 58386] ACPI: Looking for DSDT ... not found! (message during boot)

[jerryb]

Public bug reported:

on my ASUS M2nPV-VM mainboard with AMD64-X2 CPU running 2.6.15.26, I
receive this error message:

ACPI: Looking for DSDT ... not found!

I filed this as a kernel bug

http://bugzilla.kernel.org/show_bug.cgi?id=7089

but was told that:

"This message is not in the kernel.org kernel source tree, either
as of 2.6.15, or as of 2.6.18. While your system seems to have
plenty of other problems, ACPI did find the DSDT and it is running
normally.

"I expect this message comes from the "initrd DSDT override patch"
that some distributions, such as SuSE and Ubuntu tend to add to
the kernel."

Since this is apparently not a real kernel bug, but something to do with
ubuntu's initrd, I am posting the bug here

** Affects: linux (upstream)
Importance: Unknown
Status: Unknown
** Affects: linux-source-2.6.15 (Ubuntu)
Importance: Undecided
Assignee: J?r?mie Corbier
Status: Rejected

[Matthew Garrett]

The message is a harmless indication that no DSDT was found in the
initramfs.

** Changed in: initrd-tools (Ubuntu)
Sourcepackagename: initrd-tools => linux-source-2.6.15
Status: Confirmed => Rejected

[Bug Watch Updater]

** Changed in: linux (upstream)
Status: Unknown => Rejected

[Bogdan Butnaru]

Re-opening (I think). Even if this is not a real "error" (ie, if not
having a DSDT is a normal situation), this is still a user-interface
bug: it should not be reported as a boot-time error. The message should
be changed to something more descriptive, like "file /DSDT.aml not
found, using defaults" or whatever is appropriate.

I couldn't find any recent docs on this, what is it supposed to do,
anyway? I'm always having issues with ACPI and I'm always on the look
for hacks. Is there anything I can do (ie, compile a file) and perhaps
include it in a package to help support my laptop type better (Dell
Latitude D620).

I'm attaching 2.6.22 too, as I still get this message on Gutsy with the
newest kernel.

** Also affects: linux-source-2.6.22 (Ubuntu)
Importance: Undecided
Status: New

** Changed in: linux-source-2.6.15 (Ubuntu)
Status: Invalid => New

[Jérémie Corbier]

** Changed in: linux-source-2.6.15 (Ubuntu)
Assignee: J?r?mie Corbier => (unassigned)

[TJ]

The purpose of this optional kernel feature, enabled by
"CONFIG_ACPI_CUSTOM_DSDT_INITRD=y" in the kernel .config at build-time,
is to allow the user to replace the BIOS Advanced Configuration & Power
Interface (ACPI) Differentiated System Description Table (DSDT) with one
that has been modified to solve problems in the BIOS shipped by
manufacturers.

The message you see is correct. As far as the kernel is concerned it is
an error because it is told to expect to find a replacement DSDT.aml and
it isn't there. However the message could be altered somewhat to make it
sound less harsh.

Once a modified DSDT has been built using the Intel iasl tool it is
copied to /etc/initramfs-tools/DSDT.aml and the initrd image rebuilt:

$ sudo dpkg-reconfigure linux-image-$(uname -r)

This installs the DSDT to /DSDT.aml in the initrd image.

The functionality (and messages you see) is implemented in
drivers/acpi/osl.c::acpi_find_dsdt_initrd(void)

For more information, see: https://help.ubuntu.com/community/ACPIBattery

[TJ]

Update to reflect status for 2.6.22

** Changed in: linux-source-2.6.22 (Ubuntu)
Importance: Undecided => Wishlist
Assignee: (unassigned) => Ubuntu Kernel ACPI Team
Status: New => Confirmed

** Changed in: linux-source-2.6.15 (Ubuntu)
Importance: Undecided => Wishlist
Assignee: (unassigned) => Ubuntu Kernel ACPI Team
Status: New => Won't Fix

[Leann Ogasawara]

This bug does not qualify as a stable release update candidate for Gutsy
and is being closed. Thanks.

** Changed in: linux-source-2.6.22 (Ubuntu)
Status: Confirmed => Won't Fix

[Verstraete Linard]

Still there in Hardy

** Also affects: linux-source-2.6.24 (Ubuntu)
Importance: Undecided
Status: New

** Changed in: linux (Ubuntu)
Sourcepackagename: linux-source-2.6.24 => linux
Assignee: (unassigned) => Ubuntu Kernel ACPI Team (ubuntu-kernel-acpi)

[Matt Zimmerman]

The problem here is that the message is not clear enough. It looks like
an error message, but it is not. In fact, nearly every Ubuntu system
logs this message on every boot.

It simply means that there is no DSDT override included in the
initramfs, and it should say that instead. This should be a one-line
patch. I suggest:

ACPI: Checking for DSDT override... (none found)


** Changed in: linux (Ubuntu)
Importance: Undecided => Low
Status: New => Triaged

[Mark Falcey]

Well, the message says error so what should people expect.

I found this while perusing the logs after upgrading to 2.6.24-18.32
generic about an hour ago:

ACPI: Looking for DSDT in initramfs... error, file /DSDT.aml not found.

[Matt Zimmerman]

Post by Mark Falcey
Well, the message says error so what should people expect.

It may not have been sufficiently clear from my comment, but I was
suggesting changing it (including removing the word "error") for that
reason.

[vmc]

I have a Dell Optiplex GX270. When I grep the dmesg I get the error that
this bug report shows.

I then did this:
~ sudo cp /proc/acpi/dsdt .
~ sudo iasl -d dsdt
~ sudo iasl -sa dsdt.ds

After it compiles I get this Warning:

dsdt.dsl 1052: Method (_S5D, 0, NotSerialized)
Warning 1097 - Unknown reserved name ^ (_S5D)

ASL Input: dsdt.dsl - 3213 lines, 108415 bytes, 1051 keywords
AML Output: dsdt.aml - 9858 bytes 394 named objects 657 executable opcodes

Compilation complete. 0 Errors, 1 Warnings, 0 Remarks, 257 Optimizations

I tried tracking down "Method (_S5D", but couldn't find anything. I get
close but no cigar.

[Colin King]

** Changed in: linux (Ubuntu)
Assignee: Ubuntu Kernel ACPI Team (ubuntu-kernel-acpi) => Colin King (colin-king)
Status: Triaged => In Progress

[Colin King]

** Changed in: linux (Ubuntu)
Status: In Progress => Fix Committed

[Leann Ogasawara]

Setting this to Fix Released for Intrepid as I believe the message has
been reworded to "ACPI: Checking initramfs for custom DSDT" . Thanks.

** Changed in: linux (Ubuntu)
Status: Fix Committed => Fix Released