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25 Posts

11-05-2011

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W520 BIOS Bug? (Please fix or comment, Lenovo)

2012-07-19, 3:16 AM

After much digging, seems as though there is a BIOS bug on the W520 BIOS. The Linux kernel dev's found it, but this still applies to other operating systems, include windows.

 

In summary from (https://groups.google.com/forum/?fromgroups#!topic/fa.linux.kernel/iCAzjSyIHdI):

1. W520 BIOS reports CPU is X2APIC capable

2. W520 BIOS does not export DMAR table, which is needed to enable interrupt remapping in the kernel

3. OS Kernel Hangs on boot since it it thinks CPU is X2APIC capable, does not have the information to enable it.

 

Seems as though this works in Windows, but not Linux. If the CPU is X2APIC cabable though, I do not see how windows can make use of this cpu feature without a DMAR table, so it must fall back to XAPIC, which means those who bought this machine from Lenovo with its advertised specifications do not get the features we expected.

 

This is a definite BIOS bug which I hope is addressed. The Linux kernel devs are working to fallback to XAPIC so it does not cause boot issues, but the bug still remains where we have X2APIC capable hardware but due to a BIOS bug we do not get the feature.

 

Excuse me if I got some of the wording wrong, I am far from a kernel developer. How can those who own this machine receive a BIOS fix? I have tried to report it VIA phone, but I am just ignored and passed to the community forums. Also the phone tech's give me grief about running anything but windows and refuse to listen to anything to I have to say about the faulty product that was sold to me :(

 

Any help appreciated on how to get a fix from Lenovo (either do not report X2APIC capabilty or export a DMAR table in the BIOS).

 

Thanks ...

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2 Posts

10-19-2012

United States

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Re: W520 BIOS Bug? (Please fix or comment, Lenovo)

2012-10-19, 20:10 PM

Is anyone at Lenovo listening?

 

The BIOS is broken, please fix this bug.  It's affecting both Windows and Linux users.

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7173 Posts

06-27-2008

United States of America

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  • Message 3 of 15

Re: W520 BIOS Bug? (Please fix or comment, Lenovo)

2012-10-19, 20:20 PM

have you confirmed that the issue remains in the most current BIOS?

the original post is from July and the most recent BIOS (v1.39) shows a date of 10/2/2012 in the driver matrix:

http://support.lenovo.com/en_US/research/hints-or-tips/detail.page?&DocID=HT063273

 

regards.


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2 Posts

10-19-2012

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Re: W520 BIOS Bug? (Please fix or comment, Lenovo)

2012-10-19, 20:23 PM
Yes, I have confirmed that this is still an issue with the 1.39 version of the BIOS just released.

Thanks for the reply.
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25 Posts

11-05-2011

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  • Message 5 of 15

Re: W520 BIOS Bug? (Please fix or comment, Lenovo)

2012-10-19, 20:25 PM

Booting the linux kernel with nox2apic solves the problem. Looking around further, x2apic is about supporting more than 128 cpu's, which will not be likely on these laptops anyway. At this point all we can hope for is for linux kernel devs to implement he xapic fallback so we do not have to specfically boot with a kernel parameter to fix the problem.

 

Confirmed still broken on 1.39 as well.

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124 Posts

06-16-2010

Brooklyn, NY

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Re: W520 BIOS Bug? (Please fix or comment, Lenovo)

2012-11-09, 14:47 PM

is x2APIC merely for >128 CPU support?  I believe it has to do with more than just that...

 

There's mention on the Internet that setting VT-d off in the BIOS fixes this...  along with this, there's a rumor that re-enabling it after turning it off keeps the fix...  no one has confirmed this and I am not near my machine to verify.

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14 Posts

10-31-2012

L5L6B1

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  • Message 7 of 15

Re: W520 BIOS Bug? (Please fix or comment, Lenovo)

2012-11-14, 17:50 PM

wrote:

is x2APIC merely for >128 CPU support?  I believe it has to do with more than just that...

 

There's mention on the Internet that setting VT-d off in the BIOS fixes this...  along with this, there's a rumor that re-enabling it after turning it off keeps the fix...  no one has confirmed this and I am not near my machine to verify.


Is there a way/tool to see/test this in Windows for o/s independant confirmation?

 

Not to hijack this thread but I wonder if the suggestion to disable VT-d bypasses this of sorts. Would explain misc booting issues with Windows 8 related to having VT-d on? I definitely don't know what I'm talking about though.

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124 Posts

06-16-2010

Brooklyn, NY

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  • Message 8 of 15

Re: W520 BIOS Bug? (Please fix or comment, Lenovo)

2012-11-14, 19:08 PM

Definitely confirmed this with kernel 3.2.x and disabling VT-d in the BIOS.  Without disabling this, I have not been able to workaround this via any kernel manipulations the way some have been able to.  Can't comment on Windows 7/8 since Windows 7 works fine for me whether VT-d is enabled or disabled.  Kernel 2.6.x worked fine as well with VT-d enabled.  There's rumors the newer 3.4.x or 3.6.x fixes this...

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4 Posts

01-04-2014

Switzerland

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  • Message 9 of 15

Re: W520 BIOS Bug? (Please fix or comment, Lenovo)

2014-09-04, 9:50 AM

The same boot hang also occurs for me on a Lenovo W530 with Fedora 20.

Steps to reproduce

1. BIOS:
   - Configure for Discrete Graphics  
   - Enable VT-x and VT-d under Security -> Virtualization
2. Use Nvidia driver
3. Configure kernel commandline *without* nox2apic
4. Boot Fedora
5. Early boot hang when udev becomes active, close to the likely unrelated "Could not configure common clock" message

Boot hang is 100% reproducible with the S/W versions shown below.
I'm using BIOS version 2.53, not sure if 2.59 (latest version) would make any difference -- the README is too vague.

Option A to avoid boot hang (preferred):
Steps as above, but add nox2apic to kernel commandline

Option B to avoid boot hang:
Steps as above, but disable VT-d in BIOS


Digging further, I found the following related bugs, and infos [2] on the
workaround combining VT-x + VT-d with the nox2apic kernel parameter,
which is preferable to disabling VT-d:

[1] https://bugzilla.kernel.org/show_bug.cgi?id=43054
[2] https://lkml.org/lkml/2011/5/23/196
[3] https://groups.google.com/forum/?fromgroups#!topic/fa.linux.kernel/iCAzjSyIHdI
[4] http://forums.lenovo.com/t5/W-Series-ThinkPad-Laptops/W520-BIOS-Bug-Please-fix-or-comment-Lenovo/td-p/802085
[5] http://forums.lenovo.com/t5/Linux-Discussion/W520-Debian-64-bit-Testing-VT-enabled/td-p/671621

It can be extremely difficult to figure out that nox2apic is needed for W530 because the x2apic-related boot hang occurs so early.

==>  A much better solution would be to resolve the x2apic-related BIOS issue discussed in the above threads.

As an IBMer, I would be grateful if Lenovo would try to correct a little bit the impression that the Linux community is being ignored since the ThinkPad business went to Lenovo.

Thank you for your consideration !


Installed BIOS, kernel and driver

# dmidecode -s bios-version && dmidecode -t11
G5ET93WW (2.53 )
# dmidecode 2.12
SMBIOS 2.7 present.
(latest BIOS is 2.59, unclear from README if it's worth updating)

# uname -r
3.15.10-201.fc20.x86_64

kmod-nvidia-3.15.10-201.fc20.x86_64-331.89-2.fc20.10.x86_64

 

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25 Posts

11-05-2011

USA

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  • Message 10 of 15

Re: W520 BIOS Bug? (Please fix or comment, Lenovo)

2014-09-04, 10:52 AM

Just an update on my side.

 

The bug still exists in discrete mode, however I have been using optimus mode for quite some time, now that optimus works almost flawlessly in linux, thus avoiding the issue all together.

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