Bug 744659

Summary: kernel hangs during boot if IOMMU enabled on Supermicro H8DG6-F
Product: Red Hat Enterprise Linux 5 Reporter: starlight
Component: kernelAssignee: Red Hat Kernel Manager <kernel-mgr>
Status: CLOSED NOTABUG QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 5.7   
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-10-14 15:19:12 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Attachments:
Description Flags
successful EL5 boot 'dmesg' with IOMMU disabled
none
successful EL6 boot with IOMMU *enabled*
none
dmidecode
none
lspci
none
lspci -vvv none

Description starlight 2011-10-10 03:17:51 UTC 
Created attachment 527130 [details]
successful EL5 boot 'dmesg' with IOMMU disabled

Description of problem:

If IOMMU is enabled in BIOS on Supermicro H8DG6-F
system hangs after the line

   ACPI: DMAR not present

is displayed.  Tried booting with 'intel_iommu=off'
but it did not help.  System works fine with
IOMMU disabled in BIOS and boots into
RHEL6 2.6.32-71.29.1.el6 no problem with IOMMU
enabled.  Also boots Windows 2008 R2 with IOMMU
enabled.

Version-Release number of selected component (if applicable):

kernel 2.6.18-274.3.1.el5

How reproducible:

Enable IOMMU in BIOS.

Boot system.
  
Actual results:

Hangs during boot at "ACPI: DMAR not present"

Expected results:

should boot ok

Additional info:

one Opteron 6174 CPU, 16GB DDR3 RAM
Comment 1 starlight 2011-10-10 03:18:47 UTC 
Created attachment 527131 [details]
successful EL6 boot with IOMMU *enabled*
Comment 2 starlight 2011-10-10 03:19:49 UTC 
Created attachment 527132 [details]
dmidecode
Comment 3 starlight 2011-10-10 03:20:09 UTC 
Created attachment 527133 [details]
lspci
Comment 4 starlight 2011-10-10 03:20:31 UTC 
Created attachment 527134 [details]
lspci -vvv
Comment 5 starlight 2011-10-11 06:17:46 UTC 
Never mind.

BIOS v2.0 fixes it.