今天想用一下显示器自带的喇叭，忽然发现声音输出选项里HDMI的声音设备没了。之前开始使用这台显示器的时是用过一段时间的。
百度了一番，没发现什么线索。后来去谷歌找到这么一段文字：
I'm not sure where to report this, but after I upgraded a Lenovo Y50 laptop to Win 10 64 Enterprise, the HDMI audio stopped working.
All the drivers were installed, and the correct options were selected in the audio panel.
After much research I stumbled upon a post on a message board which had a suggestion that didn't make any sense, but I tried it anyway, and it resolved the issue.
The suggestion was to uninstall Hyper-V.
Once the Hyper-V feature was uninstalled from Windows, HDMI audio started working again.
It seems that for whatever reason, Hyper-V is interfering with HDMI audio out in Windows 10.
This problem did not exist in 8.1
Can you guys look into this?
随便浏览一下，大概是跟Hyper-V有关系。我查看了一下，Hyper-V之前，因为一个什么原因，被我暂时卸载停用了。（记得当时HDMI有输出声音的时候，是有Hyper-V在的）
于是，重新把Hyper-V激活，重启电脑后，HDMI的声音输出设备又回来了。
貌似，我的情况跟上面搜索到的情况相反。但都是跟Hyper-V的启用和禁用有关系。
电脑配置：Dell XPS 15z,
操作系统：Windows10 专业版，英文版本
显示器： LG-29UC97C