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[Bug 1037094] Re: "writing `/dev/mem': Bad address" Error writing to ACPI area with 32 bit kernel

 

Colin Law, given bug 806032 is resolved for you, would you need anyone
to look into this, or may this be closed as Status Invalid?

** Changed in: linux (Ubuntu)
       Status: Confirmed => Incomplete

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Title:
  "writing `/dev/mem': Bad address" Error writing to ACPI area with 32
  bit kernel

Status in “linux” package in Ubuntu:
  Incomplete

Bug description:
  Using the 32 bit kernel I am unable to write to the ACPI memory area
  using the command

  sudo dd if=value_file of=/dev/mem bs=1 seek=3660685688 count=4
  This gives the error
  dd: writing `/dev/mem': Bad address

  3660685688 is 0xDA31A178 and sudo cat /proc/iomem shows
  ...
  da216000-da32bfff : ACPI Non-volatile Storage
  ...

  This works ok with the 64 bit kernel.
  I have also tested it with the Oneiric kernel 3.0.0-12 and again the 64 bit kernel is ok but the 32 bit gives the error.

  In case it is relevant the context is that I am trying to apply the workaround for bug #806032 (
  Fn + F[89] does not work for controlling brightness on Clevo laptops) described in comment #7, which works perfectly on the 64 bit kernel but gives Bad Address error on 32 bit.

  ProblemType: Bug
  DistroRelease: Ubuntu 12.10
  Package: linux-image-3.5.0-10-generic 3.5.0-10.10
  ProcVersionSignature: Ubuntu 3.5.0-10.10-generic 3.5.1
  Uname: Linux 3.5.0-10-generic i686
  ApportVersion: 2.4-0ubuntu6
  Architecture: i386
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  colinl     2142 F.... pulseaudio
  Date: Wed Aug 15 13:42:37 2012
  HibernationDevice: RESUME=UUID=386e4578-bf9d-4970-a10f-b0b513b32771
  InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha i386 (20120730.1)
  MachineType: CLEVO CO. W240EU/W250EUQ/W270EUQ
  ProcEnviron:
   LANGUAGE=en_GB:en
   TERM=xterm
   PATH=(custom, user)
   LANG=en_GB.UTF-8
   SHELL=/bin/bash
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-10-generic root=UUID=c5043680-f556-4f19-9e32-c6fdb4c05f9e ro quiet splash vt.handoff=7
  RelatedPackageVersions:
   linux-restricted-modules-3.5.0-10-generic N/A
   linux-backports-modules-3.5.0-10-generic  N/A
   linux-firmware                            1.88
  RfKill:
   0: phy0: Wireless LAN
   	Soft blocked: no
   	Hard blocked: yes
  SourcePackage: linux
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 02/24/2012
  dmi.bios.vendor: American Megatrends Inc.
  dmi.bios.version: 4.6.5
  dmi.board.asset.tag: Tag 12345
  dmi.board.name: W240EU/W250EUQ/W270EUQ
  dmi.board.vendor: CLEVO CO.
  dmi.board.version: V3.0
  dmi.chassis.asset.tag: No Asset Tag
  dmi.chassis.type: 10
  dmi.chassis.vendor: No Enclosure
  dmi.chassis.version: N/A
  dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4.6.5:bd02/24/2012:svnCLEVOCO.:pnW240EU/W250EUQ/W270EUQ:pvrNotApplicable:rvnCLEVOCO.:rnW240EU/W250EUQ/W270EUQ:rvrV3.0:cvnNoEnclosure:ct10:cvrN/A:
  dmi.product.name: W240EU/W250EUQ/W270EUQ
  dmi.product.version: Not Applicable
  dmi.sys.vendor: CLEVO CO.

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