求助!Ubuntu Kylin 14.04 登录界面有声音,但是进入系统以后没有声音

[AdreaPirlo]

台式机,HDMI线接显示器扬声器,登录界面的时候显示器有声音,但是登入系统之后显示器就没声音了.好奇怪.
另外,登入系统之后,插入耳机,在测试音量的时候是有声音的,但是打开网页看视频,用播放器看电影的时候,耳机也没声音了.

sudo lshw -numeric -class multimedia

代码： 全选

*-multimedia            
       description: Audio device
       product: Barts HDMI Audio [Radeon HD 6800 Series] [1002:AA88]
       vendor: Advanced Micro Devices, Inc. [AMD/ATI] [1002]
       physical id: 0.1
       bus info: pci@0000:01:00.1
       version: 00
       width: 64 bits
       clock: 33MHz
       capabilities: pm pciexpress msi bus_master cap_list
       configuration: driver=snd_hda_intel latency=0
       resources: irq:52 memory:f7e40000-f7e43fff
  *-multimedia
       description: Audio device
       product: 7 Series/C210 Series Chipset Family High Definition Audio Controller [8086:1E20]
       vendor: Intel Corporation [8086]
       physical id: 1b
       bus info: pci@0000:00:1b.0
       version: 04
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list
       configuration: driver=snd_hda_intel latency=0
       resources: irq:50 memory:f7f10000-f7f13fff

sudo lspci -knn | grep Audio

代码： 全选

00:1b.0 Audio device [0403]: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller [8086:1e20] (rev 04)
01:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] Barts HDMI Audio [Radeon HD 6800 Series] [1002:aa88]

[AdreaPirlo]

我在bios设置里把主板的声卡禁用了,这下连登录页面也没有声音了...