你们好，
我们公司用AM572x IDK 这块板子，但是官方没有提供ubuntu环境，前两周我成功在上面搭建了Ubuntu rootfs，可以进入字符界面，但是还需要一个ubuntu-desktop,
可是无论如何我都无法成功启动Xorg,每当我statrx时候，/var/log/Xorg.0.log 日志内容是
[ 934.808]
X.Org X Server 1.15.1
Release Date: 2014-04-13
[ 934.808] X Protocol Version 11, Revision 0
[ 934.808] Build Operating System: Linux 4.4.0-83-generic armv7l Ubuntu
[ 934.808] Current Operating System: Linux ubuntu-arm 4.9.28-rt16-g786e64041b #2 SMP PREEMPT RT Wed Jun 28 17:47:44 EDT 2017 armv7l
[ 934.808] Kernel command line: console=ttyO2,115200n8 video=HDMI-A-1:1920x1080 root=PARTUUID=0008f20c-02 rw rootfstype=ext4 rootwait
[ 934.808] Build Date: 20 July 2017 07:11:27PM
[ 934.808] xorg-server 2:1.15.1-0ubuntu2.9 (For technical support please see http://www.ubuntu.com/support)
[ 934.808] Current version of pixman: 0.30.2
[ 934.808] Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
[ 934.809] Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[ 934.809] (==) Log file: "/var/log/Xorg.0.log", Time: Thu Jan 1 09:15:34 1970
[ 934.811] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[ 934.812] (==) No Layout section. Using the first Screen section.
[ 934.812] (==) No screen section available. Using defaults.
[ 934.812] (**) |-->Screen "Default Screen Section" (0)
[ 934.812] (**) | |-->Monitor "<default monitor>"
[ 934.813] (==) No monitor specified for screen "Default Screen Section".
Using a default monitor configuration.
[ 934.813] (==) Automatically adding devices
[ 934.813] (==) Automatically enabling devices
[ 934.813] (==) Automatically adding GPU devices
[ 934.813] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[ 934.813] Entry deleted from font path.
[ 934.813] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist.
[ 934.813] Entry deleted from font path.
[ 934.813] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist.
[ 934.813] Entry deleted from font path.
[ 934.813] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist.
[ 934.813] Entry deleted from font path.
[ 934.814] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist.
[ 934.814] Entry deleted from font path.
[ 934.814] (==) FontPath set to:
/usr/share/fonts/X11/misc,
/usr/share/fonts/X11/Type1,
built-ins
[ 934.814] (==) ModulePath set to "/usr/lib/arm-linux-gnueabihf/xorg/extra-modules,/usr/lib/xorg/extra-modules,/usr/lib/xorg/modules"
[ 934.814] (II) The server relies on udev to provide the list of input devices.
If no devices become available, reconfigure udev or disable AutoAddDevices.
[ 934.814] (II) Loader magic: 0x7f739f10
[ 934.814] (II) Module ABI versions:
[ 934.814] X.Org ANSI C Emulation: 0.4
[ 934.814] X.Org Video Driver: 15.0
[ 934.814] X.Org XInput driver : 20.0
[ 934.814] X.Org Server Extension : 8.0
[ 934.815] (II) xfree86: Adding drm device (/dev/dri/card1)
[ 934.815] (II) xfree86: Adding drm device (/dev/dri/card0)
[ 934.816] Initializing built-in extension Generic Event Extension
[ 934.816] Initializing built-in extension SHAPE
[ 934.816] Initializing built-in extension MIT-SHM
[ 934.816] Initializing built-in extension XInputExtension
[ 934.816] Initializing built-in extension XTEST
[ 934.816] Initializing built-in extension BIG-REQUESTS
[ 934.816] Initializing built-in extension SYNC
[ 934.816] Initializing built-in extension XKEYBOARD
[ 934.816] Initializing built-in extension XC-MISC
[ 934.816] Initializing built-in extension SECURITY
[ 934.816] Initializing built-in extension XINERAMA
[ 934.816] Initializing built-in extension XFIXES
[ 934.816] Initializing built-in extension RENDER
[ 934.816] Initializing built-in extension RANDR
[ 934.816] Initializing built-in extension COMPOSITE
[ 934.816] Initializing built-in extension DAMAGE
[ 934.816] Initializing built-in extension MIT-SCREEN-SAVER
[ 934.816] Initializing built-in extension DOUBLE-BUFFER
[ 934.816] Initializing built-in extension RECORD
[ 934.816] Initializing built-in extension DPMS
[ 934.817] Initializing built-in extension Present
[ 934.817] Initializing built-in extension DRI3
[ 934.817] Initializing built-in extension X-Resource
[ 934.817] Initializing built-in extension XVideo
[ 934.817] Initializing built-in extension XVideo-MotionCompensation
[ 934.817] Initializing built-in extension SELinux
[ 934.817] Initializing built-in extension XFree86-VidModeExtension
[ 934.817] Initializing built-in extension XFree86-DGA
[ 934.817] Initializing built-in extension XFree86-DRI
[ 934.817] Initializing built-in extension DRI2
[ 934.817] (II) LoadModule: "glx"
[ 934.818] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[ 934.826] (II) Module glx: vendor="X.Org Foundation"
[ 934.826] compiled for 1.15.1, module version = 1.0.0
[ 934.826] ABI class: X.Org Server Extension, version 8.0
[ 934.826] (==) AIGLX enabled
[ 934.826] Loading extension GLX
[ 934.826] (==) Matched omap as autoconfigured driver 0
[ 934.826] (==) Matched modesetting as autoconfigured driver 1
[ 934.826] (==) Matched fbdev as autoconfigured driver 2
[ 934.826] (==) Assigned the driver to the xf86ConfigLayout
[ 934.826] (II) LoadModule: "omap"
[ 934.827] (II) Loading /usr/lib/xorg/modules/drivers/omap_drv.so
[ 934.828] (II) Module omap: vendor="X.Org Foundation"
[ 934.828] compiled for 1.15.0, module version = 0.83.0
[ 934.828] Module class: X.Org Video Driver
[ 934.828] ABI class: X.Org Video Driver, version 15.0
[ 934.828] (II) LoadModule: "modesetting"
[ 934.829] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
[ 934.829] (II) Module modesetting: vendor="X.Org Foundation"
[ 934.829] compiled for 1.15.0, module version = 0.8.1
[ 934.829] Module class: X.Org Video Driver
[ 934.829] ABI class: X.Org Video Driver, version 15.0
[ 934.829] (II) LoadModule: "fbdev"
[ 934.830] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so
[ 934.830] (II) Module fbdev: vendor="X.Org Foundation"
[ 934.830] compiled for 1.15.0, module version = 0.4.4
[ 934.830] Module class: X.Org Video Driver
[ 934.830] ABI class: X.Org Video Driver, version 15.0
[ 934.830] (II) OMAP: Driver for TI OMAP: OMAP3430 with PowerVR SGX530,
OMAP3630 with PowerVR SGX530, OMAP4430 with PowerVR SGX540,
OMAP4460 with PowerVR SGX540, OMAP5430 with PowerVR SGX544 MP,
OMAP5432 with PowerVR SGX544 MP
[ 934.831] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[ 934.831] (II) FBDEV: driver for framebuffer: fbdev
[ 934.831] (--) using VT number 8
[ 935.038] (WW) Falling back to old probe method for omap
[ 935.167] (II) modesetting(G0): using drv /dev/dri/card0
[ 935.167] (WW) Falling back to old probe method for modesetting
[ 935.167] (WW) Falling back to old probe method for fbdev
[ 935.167] (II) Loading sub module "fbdevhw"
[ 935.167] (II) LoadModule: "fbdevhw"
[ 935.168] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[ 935.168] (II) Module fbdevhw: vendor="X.Org Foundation"
[ 935.168] compiled for 1.15.1, module version = 0.0.2
[ 935.168] ABI class: X.Org Video Driver, version 15.0
[ 935.168] (WW) VGA arbiter: cannot open kernel arbiter, no multi-card support
[ 935.169] (II) OMAP(0): Creating default Display subsection in Screen section
"Default Screen Section" for depth/fbbpp 24/32
[ 935.169] (==) OMAP(0): Depth 24, (==) framebuffer bpp 32
[ 935.169] (==) OMAP(0): RGB weight 888
[ 935.169] (==) OMAP(0): Using gamma correction (1.0, 1.0, 1.0)
[ 935.169] (==) OMAP(0): Default visual is TrueColor
[ 935.271] (EE) OMAP(0): ERROR: Unknown chipset: (null)
[ 935.271] (II) UnloadModule: "omap"
[ 935.271] (==) modesetting(G0): Depth 24, (==) framebuffer bpp 32
[ 935.272] (==) modesetting(G0): RGB weight 888
[ 935.272] (==) modesetting(G0): Default visual is TrueColor
[ 935.272] (II) modesetting(G0): ShadowFB: preferred NO, enabled NO
[ 935.400] (II) modesetting(G0): Output HDMI-1-0 has no monitor section
[ 935.531] (II) modesetting(G0): EDID for output HDMI-1-0
[ 935.531] (II) modesetting(G0): Manufacturer: PHL Model: c11d Serial#: 9892
[ 935.531] (II) modesetting(G0): Year: 2017 Week: 15
[ 935.531] (II) modesetting(G0): EDID Version: 1.3
[ 935.531] (II) modesetting(G0): Digital Display Input
[ 935.531] (II) modesetting(G0): Max Image Size [cm]: horiz.: 48 vert.: 27
[ 935.531] (II) modesetting(G0): Gamma: 2.20
[ 935.531] (II) modesetting(G0): DPMS capabilities: Off
[ 935.531] (II) modesetting(G0): Supported color encodings: RGB 4:4:4 YCrCb 4:4:4
[ 935.531] (II) modesetting(G0): First detailed timing is preferred mode
[ 935.531] (II) modesetting(G0): redX: 0.653 redY: 0.337 greenX: 0.322 greenY: 0.611
[ 935.531] (II) modesetting(G0): blueX: 0.153 blueY: 0.061 whiteX: 0.313 whiteY: 0.329
[ 935.531] (II) modesetting(G0): Supported established timings:
[ 935.531] (II) modesetting(G0): 720x400@70Hz
[ 935.531] (II) modesetting(G0): 640x480@60Hz
[ 935.531] (II) modesetting(G0): 640x480@67Hz
[ 935.531] (II) modesetting(G0): 640x480@72Hz
[ 935.531] (II) modesetting(G0): 640x480@75Hz
[ 935.531] (II) modesetting(G0): 800x600@60Hz
[ 935.531] (II) modesetting(G0): 800x600@75Hz
[ 935.531] (II) modesetting(G0): 1024x768@60Hz
[ 935.531] (II) modesetting(G0): 1024x768@75Hz
[ 935.531] (II) modesetting(G0): 1280x1024@75Hz
[ 935.532] (II) modesetting(G0): Manufacturer's mask: 0
[ 935.532] (II) modesetting(G0): Supported standard timings:
[ 935.532] (II) modesetting(G0): #0: hsize: 1920 vsize 1080 refresh: 60 vid: 49361
[ 935.532] (II) modesetting(G0): #1: hsize: 1440 vsize 900 refresh: 60 vid: 149
[ 935.532] (II) modesetting(G0): #2: hsize: 1440 vsize 900 refresh: 75 vid: 3989
[ 935.532] (II) modesetting(G0): #3: hsize: 1680 vsize 1050 refresh: 60 vid: 179
[ 935.532] (II) modesetting(G0): #4: hsize: 1280 vsize 720 refresh: 60 vid: 49281
[ 935.532] (II) modesetting(G0): #5: hsize: 1280 vsize 1024 refresh: 60 vid: 32897
[ 935.532] (II) modesetting(G0): #6: hsize: 1280 vsize 960 refresh: 60 vid: 16513
[ 935.532] (II) modesetting(G0): Supported detailed timing:
[ 935.532] (II) modesetting(G0): clock: 148.5 MHz Image Size: 477 x 268 mm
[ 935.532] (II) modesetting(G0): h_active: 1920 h_sync: 2008 h_sync_end 2052 h_blank_end 2200 h_border: 0
[ 935.532] (II) modesetting(G0): v_active: 1080 v_sync: 1084 v_sync_end 1089 v_blanking: 1125 v_border: 0
[ 935.532] (II) modesetting(G0): Serial No: UHB1715009892
[ 935.532] (II) modesetting(G0): Monitor name: PHL 226V6
[ 935.532] (II) modesetting(G0): Ranges: V min: 56 V max: 76 Hz, H min: 30 H max: 83 kHz, PixClock max 175 MHz
[ 935.532] (II) modesetting(G0): EDID (in hex):
[ 935.532] (II) modesetting(G0): 00ffffffffffff00410c1dc1a4260000
[ 935.532] (II) modesetting(G0): 0f1b010380301b782a5a65a756529c27
[ 935.532] (II) modesetting(G0): 0f5054bd4b00d1c09500950fb30081c0
[ 935.532] (II) modesetting(G0): 818081400101023a801871382d40582c
[ 935.532] (II) modesetting(G0): 4500dd0c1100001e000000ff00554842
[ 935.532] (II) modesetting(G0): 31373135303039383932000000fc0050
[ 935.533] (II) modesetting(G0): 484c2032323656360a202020000000fd
[ 935.533] (II) modesetting(G0): 00384c1e5311000a2020202020200058
[ 935.533] (II) modesetting(G0): Printing probed modes for output HDMI-1-0
[ 935.533] (II) modesetting(G0): Modeline "1920x1080"x60.0 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync (67.5 kHz eP)
[ 935.533] (II) modesetting(G0): Modeline "1680x1050"x59.9 119.00 1680 1728 1760 1840 1050 1053 1059 1080 +hsync -vsync (64.7 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "1280x1024"x75.0 135.00 1280 1296 1440 1688 1024 1025 1028 1066 +hsync +vsync (80.0 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "1280x1024"x60.0 108.00 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync (64.0 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "1440x900"x75.0 136.75 1440 1536 1688 1936 900 903 909 942 -hsync +vsync (70.6 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "1440x900"x59.9 88.75 1440 1488 1520 1600 900 903 909 926 +hsync -vsync (55.5 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "1280x960"x60.0 108.00 1280 1376 1488 1800 960 961 964 1000 +hsync +vsync (60.0 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "1280x720"x60.0 74.25 1280 1390 1430 1650 720 725 730 750 +hsync +vsync (45.0 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "1024x768"x75.0 78.75 1024 1040 1136 1312 768 769 772 800 +hsync +vsync (60.0 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "1024x768"x60.0 65.00 1024 1048 1184 1344 768 771 777 806 -hsync -vsync (48.4 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "800x600"x75.0 49.50 800 816 896 1056 600 601 604 625 +hsync +vsync (46.9 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "800x600"x60.3 40.00 800 840 968 1056 600 601 605 628 +hsync +vsync (37.9 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "640x480"x75.0 31.50 640 656 720 840 480 481 484 500 -hsync -vsync (37.5 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "640x480"x72.8 31.50 640 664 704 832 480 489 492 520 -hsync -vsync (37.9 kHz e)
[ 935.533] (II) modesetting(G0): Modeline "640x480"x66.7 30.24 640 704 768 864 480 483 486 525 -hsync -vsync (35.0 kHz e)
[ 935.534] (II) modesetting(G0): Modeline "640x480"x59.9 25.18 640 656 752 800 480 490 492 525 -hsync -vsync (31.5 kHz e)
[ 935.534] (II) modesetting(G0): Modeline "720x400"x70.1 28.32 720 738 846 900 400 412 414 449 -hsync +vsync (31.5 kHz e)
[ 935.534] (II) modesetting(G0): Using default gamma of (1.0, 1.0, 1.0) unless otherwise stated.
[ 935.534] (==) modesetting(G0): DPI set to (96, 96)
[ 935.534] (II) Loading sub module "fb"
[ 935.534] (II) LoadModule: "fb"
[ 935.534] (II) Loading /usr/lib/xorg/modules/libfb.so
[ 935.535] (II) Module fb: vendor="X.Org Foundation"
[ 935.535] compiled for 1.15.1, module version = 1.0.0
[ 935.535] ABI class: X.Org ANSI C Emulation, version 0.4
[ 935.535] (EE) Screen(s) found, but none have a usable configuration.
[ 935.535] (EE)
Fatal server error:
[ 935.535] (EE) no screens found(EE)
[ 935.535] (EE)
Please consult the The X.Org Foundation support
at http://wiki.x.org
for help.
[ 935.535] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[ 935.535] (EE)
[ 935.581] (EE) Server terminated with error (1). Closing log file.
无法解决！！请问怎么让AM572x通过HDMI显示ubuntu-desktop，现在如果 startx 屏幕就会一片漆黑，然后左上角一个光标在闪烁。
