Bug 186564

Summary: ACPI 2.0 systems with no XSDT fail to boot
Product: Red Hat Enterprise Linux 4 Reporter: Konrad Rzeszutek <konradr>
Component: kernelAssignee: Konrad Rzeszutek <konradr>
Status: CLOSED DUPLICATE QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 4.0CC: jbaron
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
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Clone Of: Environment:
Last Closed: 2006-03-29 14:48:57 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 181409    
Attachments:
Description Flags
Back-port from 2.6.12 to 2.6.9 none

Description Konrad Rzeszutek 2006-03-24 14:01:11 UTC 
Description of problem:

The ACPI routines make a blunt assumption that if a system is ACPI 2.0
compliant an XSDT table will be present.  This does not appear to be a
requirement of the ACPI 2.0 spec.  However, the spec does not outline how to
properly signify that no XSDT table is present.  If a BIOS leaves the XSDT
pointer field in the RSDP NULL'd or set to any other value to indicate that it
is invalid the ACPI routine will try to use this as the address of the XSDT.  
Upon failure of validating the XSDT, the ACPI system will not fall back and use
the RSDT pointer.

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

RHEL4 U1

How reproducible:

Any machine that has ACPI v2.0 without XSDT table.

Steps to Reproduce:
1. Boot Linux
  
Actual results:
Hang

Expected results:
Not hang

Additional info:

The patch for this had been submitted to the ACPI maintaners. The patch 
had been submitted as ACPI CA release. git-commit:
http://marc.theaimsgroup.com/?l=git-commits-head&m=112619202228915&w=2
Comment 1 Konrad Rzeszutek 2006-03-24 14:04:12 UTC 
Created attachment 126625 [details]
Back-port from 2.6.12 to 2.6.9

Patch applies cleanly to RHEL4 U3.
Comment 2 Konrad Rzeszutek 2006-03-24 14:10:21 UTC 
Patch posted for review.
Comment 3 Konrad Rzeszutek 2006-03-29 14:48:57 UTC 

*** This bug has been marked as a duplicate of 165809 ***