[radeon] error luego de actualizar ubuntu 18.04

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ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xorg 1:7.7+19ubuntu7.1
ProcVersionSignature: Ubuntu 4.15.0-32.35-generic 4.15.18
Uname: Linux 4.15.0-32-generic i686
.tmp.unity_support_test.0:

ApportVersion: 2.20.9-0ubuntu7.2
Architecture: i386
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
Date: Wed Aug 22 19:34:38 2018
DistUpgraded: 2018-08-22 07:17:57,952 DEBUG icon theme changed, re-reading
DistroCodename: bionic
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, including running git bisection searches
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] RS690M [Radeon Xpress 1200/1250/1270] [1002:791f] (prog-if 00 [VGA controller])
   Subsystem: Toshiba America Info Systems RS690M [Radeon Xpress 1200/1250/1270] [1179:ff60]
InstallationDate: Installed on 2018-08-21 (1 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release i386 (20160420.1)
MachineType: TOSHIBA Satellite A305D
ProcEnviron:
 LANGUAGE=es_AR:es
 PATH=(custom, no user)
 LANG=es_AR.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-32-generic root=UUID=9b46ee1c-18a4-4f7d-93a8-e0d1c81c43b0 ro quiet splash vt.handoff=1
SourcePackage: xorg
UpgradeStatus: Upgraded to bionic on 2018-08-22 (0 days ago)
dmi.bios.date: 09/16/2008
dmi.bios.vendor: Insyde Corp.
dmi.bios.version: 1.70
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.vendor: TOSHIBA
dmi.board.version: Base Board Version
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: Chassis Manufacturer
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnInsydeCorp.:bvr1.70:bd09/16/2008:svnTOSHIBA:pnSatelliteA305D:pvrPSAH0U-00P008:rvnTOSHIBA:rn:rvrBaseBoardVersion:cvnChassisManufacturer:ct10:cvrChassisVersion:
dmi.product.family: Type1Family
dmi.product.name: Satellite A305D
dmi.product.version: PSAH0U-00P008
dmi.sys.vendor: TOSHIBA
version.compiz: compiz 1:0.9.13.1+18.04.20180302-0ubuntu1
version.libdrm2: libdrm2 2.4.91-2
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.5-0ubuntu0~18.04.1
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.5-0ubuntu0~18.04.1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.6-1ubuntu4
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.5-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.0.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2
xserver.bootTime: Wed Aug 22 18:47:27 2018
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.19.6-1ubuntu4
xserver.video_driver: radeon