当我启动 Debian 时，GUI 没有启动。它会转到命令行要求登录。
andre@move-01:~$ systemctl status gdm3 service
* gdm.service - GNOME Display Manager
Loaded: loaded (/lib/systemd/system/gdm.service; enabled)
Active: active (running) since Mon 2017-01-09 13:32:21 BRST; 12min ago
Process: 952 ExecStartPre=/usr/share/gdm/generate-config (code=exited, status=0/SUCCESS)
Process: 952 ExecStartPre=/bin/sh -c [ "$(cat /etc/X11/default-display-manager 2>/dev/null)" = "/usr/sbin/gdm3" ] (code=exited, status=0/SUCCESS)
Main PID: 958 (gdm3)
CGroup: /system.slice/gdm.serivce
958 /usr/sbin/gdm3
1609 /usr/bin/Xorg :1 -novtswitch -background none -noreset -verbose 3 -auth /var/run/gdm3/auth-for-Debian-gdm-0Mifhr/database -seat seat0 -nolisten tcp vt7
* service.service
Loaded: not-found (Reason: No such file or directory)
Active: inactive (dead)
当我尝试时sudo startx，我得到这个：
(EE)
Fatal server error:
(EE) Can't read lock file /tmp/.X0-lock
(EE)
(EE)
Please consult the The X.Org Foundation support
at http://wiki.x.org
for help.
(EE)
xinit: giving up
xinit: unable to connect to X server: Connection refused
xinit: server error
我尝试过的其他命令：
update-rc.d -f gdm defaults
sudo /etc/init.d/gdm3 stop && startx
这是怎么回事？
（有类似的问题，但它们都不适合我。）
编辑
输出sudo journalctl -u gdm3：
-- Logs begin at Mon 2017-01-09 13:55:54 BRST, end at Mon 2017-01-09 14:25:33 BRST. --
编辑2
lspci | grep VGA输出：
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Tahi
PRO [Radeon HD 7950/8950 OEM / R9 280]