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如何在 Arch Linux 中保留登录会话？

tag-icon • tag-icon arch-linux audio systemd alsa logind
如何在 Arch Linux 中保留登录会话？

昨天我在 Arch Linux 中正常工作了音频，但在某些时候它又停止工作了：

$ alsamixer 
cannot open mixer: No such file or directory
$ vlc foo.mp4
...
[0x7f1388006be8] alsa audio output error: cannot open ALSA device "default": No such file or directory

alsamixer运行良好root，所以这似乎是一个权限问题。所有音频设备均属于root:audio：

$ ls -l /dev/snd
total 0
drwxr-xr-x 2 root root       80 Aug  6 22:54 by-path
crw-rw---- 1 root audio 116,  7 Aug  6 22:54 controlC0
crw-rw---- 1 root audio 116, 10 Aug  6 22:54 controlC1
crw-rw---- 1 root audio 116,  6 Aug  6 22:54 hwC0D0
crw-rw---- 1 root audio 116,  9 Aug  6 22:54 hwC1D0
crw-rw---- 1 root audio 116,  5 Aug  6 22:54 pcmC0D0c
crw-rw---- 1 root audio 116,  4 Aug  6 22:54 pcmC0D0p
crw-rw---- 1 root audio 116,  3 Aug  6 22:54 pcmC0D1p
crw-rw---- 1 root audio 116,  2 Aug  6 22:54 pcmC0D2c
crw-rw---- 1 root audio 116,  8 Aug  6 22:54 pcmC1D3p
crw-rw---- 1 root audio 116,  1 Aug  6 22:54 seq
crw-rw---- 1 root audio 116, 33 Aug  6 22:54 timer
$ getfacl /dev/snd/*
getfacl: Removing leading '/' from absolute path names
# file: dev/snd/by-path
# owner: root
# group: root
user::rwx
group::r-x
other::r-x

# file: dev/snd/controlC0
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/controlC1
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/hwC0D0
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/hwC1D0
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/pcmC0D0c
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/pcmC0D0p
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/pcmC0D1p
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/pcmC0D2c
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/pcmC1D3p
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/seq
# owner: root
# group: audio
user::rw-
group::rw-
other::---

# file: dev/snd/timer
# owner: root
# group: audio
user::rw-
group::rw-
other::---

我是不是audio根据组内推荐ALSA指令:

$ groups
wheel users

A讨论给我指了一个解释为什么添加该组是不必要的，有时甚至是有害的。从那里开始用户组信息说

标准桌面权限（如声音、3D、打印、安装等）不需要这些组，只要logind会话没有中断。

按照指示前往会话权限故障排除，我终于发现了一个差异 - 它说输出loginctl show-session $XDG_SESSION_ID应该包含Remote=noand Active=yes，但我得到以下结果：

$ loginctl show-session $XDG_SESSION_ID
ControlGroupHierarchy=/user
ResetControllers=cpu
NAutoVTs=6
KillExcludeUsers=root
KillUserProcesses=no
IdleHint=yes
IdleSinceHint=0
IdleSinceHintMonotonic=0
InhibitDelayMaxUSec=5s
HandlePowerKey=poweroff
HandleSuspendKey=suspend
HandleHibernateKey=hibernate
HandleLidSwitch=suspend
IdleAction=ignore
IdleActionUSec=30min
PreparingForShutdown=no
PreparingForSleep=no

从那里我找到了有关的信息保留会话，这似乎不适用 -/etc/X11/xinit/xserverrc自安装以来我的未经修改：

$ ls -l /etc/X11/xinit/xserverrc
-rw-r--r-- 1 root root 132 Oct 31  2012 /etc/X11/xinit/xserverrc

SLiM 似乎运行良好：

$ systemctl status slim.service
slim.service - SLiM Simple Login Manager
   Loaded: loaded (/usr/lib/systemd/system/slim.service; enabled)
   Active: active (running) since Sat 2013-08-10 00:00:39 CEST
 Main PID: 258 (slim)
   CGroup: name=systemd:/system/slim.service
           ├─ 258 /usr/bin/slim -nodaemon
           ├─ 292 /usr/bin/X -nolisten tcp vt07 -auth /var/run/slim.auth
           ├─ 416 /usr/bin/gnome-keyring-daemon --daemonize --login
           ├─ 418 awesome
           ├─ 423 /usr/bin/dbus-daemon --fork --print-pid 5 --print-address 7 --session
           ├─ 472 xscreensaver -no-splash
           ├─ 479 firefox
           ├─ 481 java -Xmx192M -jar /usr/share/java/jedit/jedit.jar -reuseview
           ├─ 483 pidgin
           ├─ 485 xterm
           ├─ 500 bash
           ├─ 581 /usr/lib/at-spi2-core/at-spi-bus-launcher
           ├─ 641 xterm
           ├─ 643 bash
           ├─1006 git gui
           ├─1007 wish /usr/lib/git-core/git-gui --
           ├─1367 dbus-launch --autolaunch e943bbb765d74fceb0393a55ceebfd1d --binary-syntax --close-stderr
           ├─1368 /usr/bin/dbus-daemon --fork --print-pid 5 --print-address 7 --session
           ├─1403 ekiga
           ├─1405 /usr/lib/GConf/gconfd-2
           ├─1476 thunar
           ├─1478 /usr/lib/xfce4/xfconf/xfconfd
           └─1589 systemctl status slim.service

我需要做什么来修复登录会话，从而（大概）修复音频权限？

答案1

问题是login_cmd作为@jasonwryan 暗示;我应该保留原始值，而不是遵循 GNOME > 2.30 配置建议上的 [SLiM + GNOME 密钥环][7]：

$ grep login_cmd /etc/slim.conf
# login_cmd           exec /bin/sh - ~/.xinitrc %session
# login_cmd           exec /bin/bash -login ~/.xinitrc %session
login_cmd           exec dbus-launch /bin/bash -login ~/.xinitrc %session >~/.xsession-errors 2>&1

恢复到 后login_cmd exec /bin/bash -login ~/.xinitrc %session，我现在获得了更明智的会话信息：

$ loginctl show-session $XDG_SESSION_ID
Id=c1
Timestamp=Fri 2013-08-09 22:30:28 CEST
TimestampMonotonic=11871667
DefaultControlGroup=systemd:/user/1000.user/c1.session
VTNr=7
Display=:0.0
Remote=no
RemoteUser=root
Service=slim
Leader=260
Audit=0
Type=x11
Class=user
Active=yes
State=active
KillProcesses=no
IdleHint=no
IdleSinceHint=0
IdleSinceHintMonotonic=0
Name=username

这实际上解决了主要问题 -vlc如果我手动将其设置为使用第一个 HDA Intel 音频设备，则能够播放视频。

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