07-15-2012 12:36 PM
I agree fully. It's unfortunate as I am happy with my Laptop otherwise, I have been running linux for the last 5 years on my previous machine, purchased the w520 and due to so many issues, I have been forced to switch back to windows :-(
I also will not be purchasing a Lenovo for my next computer.
07-16-2012 09:10 PM
same problem. this is plagued with posts all over the net. i have ran linux for so many years on and off, bought a w520, and now i cannot even boot into any distrobution without vt-d disabled (which sucks). someone already posted this, but it seems like there is a good possbility it is a bios bug:
** TO LENOVO: Please provide feedback on this. We have bought this machines only to not be able to run our operating system of choice.
07-18-2012 08:20 PM
Did some more google digging and found out some information as to why this does not work. Seems as though the linux kernel devs are working on a workaround so it does not cause a boot hang, but this involves falling back to XAPIC. The CPU is X2APIC capable though, which means we do not get this feature on the W520 unless Lenovo fixes their BIOS. This just means slower virtualization on XAPIC. Disabling VT-D seems to workaround the issue (maybe not reporting X2APIC capable CPU?)
I posted here in general, so any comments will help to get them to fix the BIOS bug:
07-18-2012 10:01 PM
I very much doubt whether lenovo have the inclination or competence to address this issue.
As I have stated before, never again lenovo.
There are enough threads in various forums, including this one, highlighting this problem.
07-25-2012 05:50 PM
Found what seems to be like a simple workaround to boot 64-bit, discrete graphics and VT-d. In the bios setup under boot, change the boot to UEFI only. I tried this on arch linux and i can successfuly boot and reboot 10 times without a boot lockup.
Not a bad workaround if you don't mind UEFI. Time to install Debian
07-28-2012 09:50 AM
07-28-2012 07:52 PM
It's not my job to fix your issues. It's your job to fix your issues... or, apparently, as you believe, Lenovo's job to fix your custom computing issues.
Your reply only underscores my previous remarks. It's very hard to be sympathetic or want to help you when you insult the people you want help from.
I rest my case.
07-29-2012 03:13 AM - edited 07-29-2012 03:18 AM
I may of found a reason why VT-D whit X2APIC is giving problems
Looking at Intels VT-D specs v1.3
You will find that there is a opt-out for X2APIC available at ch 8.1
After finding this i immediately dived into the ACPI Data Table of my Bios to look at the used setting
and this is what i found
/* * Intel ACPI Component Architecture * AML Disassembler version 20120711-32 [Jul 11 2012] * Copyright (c) 2000 - 2012 Intel Corporation * * Disassembly of RSDT_13_DMAR.BIN, Sat Jul 28 19:28:58 2012 * * ACPI Data Table [DMAR] * * Format: [HexOffset DecimalOffset ByteLength] FieldName : FieldValue */ [000h 0000 4] Signature : "DMAR" [DMA Remapping table] [004h 0004 4] Table Length : 000000B0 [008h 0008 1] Revision : 01 [009h 0009 1] Checksum : 46 [00Ah 0010 6] Oem ID : "INTEL " [010h 0016 8] Oem Table ID : "SNB " [018h 0024 4] Oem Revision : 00000001 [01Ch 0028 4] Asl Compiler ID : "INTL" [020h 0032 4] Asl Compiler Revision : 00000001 [024h 0036 1] Host Address Width : 23 [025h 0037 1] Flags : 01<- [030h 0048 2] Subtable Type : 0000 [Hardware Unit Definition] [032h 0050 2] Length : 0058 [034h 0052 1] Flags : 01 [035h 0053 1] Reserved : 00 [036h 0054 2] PCI Segment Number : 0000 [038h 0056 8] Register Base Address : 00000000FED91000
*W520 Bios 1.34 and 1.37 tested.
(Note that this are only the first 31 rows of the file and that XDRT version of the DMAR table is the same, at least what i could see in a fast look)
As you see that the Flag value that I marked is set to 1 which does the following according to the VT-D 1.3 standard
Bit 1: X2APIC_OPT_OUT - For firmware
compatibility reasons, platform firmware
may Set this field to request system
software to opt out of enabling Extended
xAPIC (X2APIC) mode. This field is valid only
when the INTR_REMAP field (bit 0) is Set.
Since firmware is permitted to hand off
platform to system software in legacy xAPIC
mode, system software is required to check
this field as Clear as part of detecting
X2APIC mode support in the platform.
What this means is that X2APIC will not work whit the current bios.
All the software is effected for this part at least
This flag may be causing problems whit the Linux boot loaders.
people have been reporting that VT-D gives almost no problems whit nox2apic added to the boot loader which is what the system is supposed to do anyway (whit X2APIC_OPT_OUT on in the DMAR table)
So there is indeed a part wrong whit the bios that Lenovo should fix
Guide how to look at your APCI table: