Here is a possible workaround.
After reading up some on ACPI, I decided it was that the system got
stuck in the BIOSs’ ACPI code. This is what the error message showed
and I also came to the (possibly wrong) conclusion that this error was
there all along and other kernel changes actually fixed something else
that made async accesses to the ACPI functions “proper”. But for us
Z580 users it created the long delay waiting for the AML interpreter to
determine that the BIOS was hung.
So I got the iasl tool, decompiled, changed and recompiled the DSDT,
then used grub to load the changed version before loading the kernel.
It worked and now there is no delay with this workaround.
The change I made was in DSDT method WAEC (wait on embedded
controller?). Here is the method along with the one line fix:
Method (WAEC, 0, NotSerialized)
{
Name (CUNT, 0x1E)
While (LNotEqual (^PCI0.LPCB.EC0.BYFG, Zero))
{
Sleep (0x05)
Decrement (CUNT)
If (LEqual (CUNT, Zero))
{
Store (Zero, ^PCI0.LPCB.EC0.BYFG)
Store (Zero, ^PCI0.LPCB.EC0.DRFG)
Break
}
}
Sleep (50) // #### adding this line is the only change ####
}
When getting battery info, this method is used 3 times. It is called
just before commanding the EC to return a different piece of battery
info. Since battery info is fetched twice for some reason, this only
adds about 300 milliseconds (a lot better than 20 minutes).
Here are the approximate steps I used:
Install the ASL compiler iasl (apt-get install iasl I think).
Make a copy of /sys/firmware/acpi/tables/DSDT
isal -d DSDT to decompile to DSDT.dsl
[Compile to aml and you see two differences, the version number of the
compiler is different]
Edit the change into DSDT.dsl
iasl DSDT.dsl to produce DSDT.aml
sudo cp DSDT.aml /boot/.
Reboot and enter ‘c’ at the grub menu, then enter “acpi /boot/DSDT.aml”,
then escape and boot (I am using 3.2.0-38-generic).
Then I edited /boot/grub/grub.cfg and put the acpi command in there. An
approach that works even with upgrades is described by Michael Kuron at
http://blog.michael.kuron-germany.de/2011/03/patching-dsdt-in-recent-
linux-kernels-without-recompiling/
I just guessed on where to put the delay. I thought it must be a race
or timing issue and I planned to shotgun delays everywhere, but got
lucky and the first one worked. Someone else may be able to determine if
there is a better fix.
By the way, you can confirm the DSDT is loaded from the line in dmesg:
[ 0.000000] ACPI: DSDT 00000000d82bc1f0 0AD5B (v02 LENOVO IVB-CPT 00000000
INTL 20100528)
The original has 20061109 I think.
Another thing I tried that did NOT help the problem was adding
acpi_serialize to kernel boot options.
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https://bugs.launchpad.net/bugs/1093217
Title:
Ubuntu 12.04 10-20min boot delay (From 3.2.0.29->3.2.0.30) [Lenovo
IdeaPad Z580]
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