startxfce4はAsus Chromebookにロードされなくなりました。

私はAcer Chromebookを持っており、「shell」を介してxfceにロードしてから、Chrome端末から「sudo startxfce4」をロードできました。突然エラーが発生し、ロードされなくなりました。代わりに、私は次のようになります。どんな提案がありますか？

chronos@localhost / $ sudo startxfce4
Entering /mnt/stateful_partition/crouton/chroots/xenial...
/usr/bin/startxfce4: Starting X server


X.Org X Server 1.18.4
Release Date: 2016-07-19
X Protocol Version 11, Revision 0
Build Operating System: Linux 4.4.0-45-generic x86_64 Ubuntu
Current Operating System: Linux localhost 3.8.11 #1 SMP Tue Oct 31 22:10:06 PDT 2017 x86_64
Kernel command line: cros_secure console= loglevel=7 init=/sbin/init cros_secure oops=panic panic=-1 root=/dev/dm-0 rootwait ro dm_verity.error_behavior=3 dm_verity.max_bios=-1 dm_verity.dev_wait=1 dm="1 vroot none ro 1,0 2539520 verity payload=PARTUUID=9feb1eec-d299-fe40-a13d-abe1410a06ae/PARTNROFF=1 hashtree=PARTUUID=9feb1eec-d299-fe40-a13d-abe1410a06ae/PARTNROFF=1 hashstart=2539520 alg=sha1 root_hexdigest=5b28e9104a0c6de57e5586e8881f487b517ac745 salt=9f9e91fe33efaf85f73ed8a2d521f9278d4e2f04c2b3165ff3f9de38cc059669" noinitrd vt.global_cursor_default=0 kern_guid=9feb1eec-d299-fe40-a13d-abe1410a06ae add_efi_memmap boot=local noresume noswap i915.modeset=1 tpm_tis.force=1 tpm_tis.interrupts=0 nmi_watchdog=panic,lapic iTCO_vendor_support.vendorsupport=3  
Build Date: 02 November 2016  10:06:10PM
xorg-server 2:1.18.4-0ubuntu0.2 (For technical support please see http://www.ubuntu.com/support) 
Current version of pixman: 0.33.6
        Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(++) Log file: "/tmp/Xorg.crouton.1.log", Time: Mon Dec 18 20:05:53 2017
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
Error org.freedesktop.DBus.Error.UnknownMethod: Method "ReleaseDisplayOwnership" with signature "" on interface "org.chromium.LibCrosServiceInterface" doesn't exist

xf86EnableIOPorts: failed to set IOPL for I/O (Operation not permitted)
Error org.freedesktop.DBus.Error.UnknownMethod: Method "ReleaseDisplayOwnership" with signature "" on interface "org.chromium.LibCrosServiceInterface" doesn't exist

xf86EnableIOPorts: failed to set IOPL for I/O (Operation not permitted)
(EE) 
Fatal server error:
(EE) AddScreen/ScreenInit failed for driver 0
(EE) 
(EE) 
Please consult the The X.Org Foundation support 
         at http://wiki.x.org
 for help. 
(EE) Please also check the log file at "/tmp/Xorg.crouton.1.log" for additional information.
(EE) 
Error org.freedesktop.DBus.Error.UnknownMethod: Method "TakeDisplayOwnership" with signature "" on interface "org.chromium.LibCrosServiceInterface" doesn't exist

(EE) Server terminated with error (1). Closing log file.

編集1：

上記のログファイル、@LiveWireBTは次のとおりです。https://people.ucsc.edu/~ianc/files/Xorg.crouton.1.log エラー行は次のとおりです。

[21.721] (EE) Modeset(0): drmSetMaster 失敗: 権限が拒否されました。

どんなアイデアがありますか？