Bug 499614

Summary: System locks up when booting with "intel_iommu=on" (BIOS bug?)
Product: [Fedora] Fedora Reporter: Rainer Koenig <Rainer.Koenig>
Component: kernelAssignee: Kernel Maintainer List <kernel-maint>
Status: CLOSED DUPLICATE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: low    
Version: rawhideCC: dwmw2, itamar, kernel-maint, markmc, quintela, virt-maint
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OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2009-05-07 13:17:10 UTC Type: ---
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Description Flags
Captured kernel messages from the serial console none

Description Rainer Koenig 2009-05-07 12:54:41 UTC
Created attachment 342832 [details]
Captured kernel messages from the serial console

Description of problem:
When the kernel is booted with bootparam intel_iommu=on the system locks up. 

Version-Release number of selected component (if applicable):
2.6.29.2-126.fc11.x86_64

How reproducible:
Always, also with different BIOS settings (e.g. Coherency="on/off")

Steps to Reproduce:
1. Intall F11-Preview
2. Reboot and edit in grub so that boot param intel_iommu=on is submitted
3. 
  
Actual results:
If you boot with params "rhgb quiet" you only see the cursor blinking in the upper left corner of the screen. If you boot without "rhgb quiet" then you see the messages that I captured in the attached file.

Expected results:
System should boot to runlevel 5.

Additional info:
Since the capture log also has a line

DMAR:Unknown DMAR structure type

U expect that the root cause of this bug can be somewhere within the BIOS. So I will contact BIOS development first to see if they can explain that. This is why this bug is currently set to low priority.

Comment 1 Mark McLoughlin 2009-05-07 13:03:21 UTC
Thanks Rainer

Comment 2 David Woodhouse 2009-05-07 13:11:16 UTC
Can you build a kernel without CONFIG_INTR_REMAP to check whether it's DMA remapping or interrupt remapping that's causing the problem?

Comment 3 David Woodhouse 2009-05-07 13:17:10 UTC
User reports that turning off legacy keyboard emulation in the BIOS fixes the hang. This seems to be a duplicate of bug 490477.

User reports an identical hang at 'starting udev', which needs to be investigated further.

*** This bug has been marked as a duplicate of bug 490477 ***