Ubuntu18.04 solution to no sound-the test was successful (including no sound after plugging in the HDML cable)

Link: https://blog.csdn.net/robertsong2004/article/details/50210907 .

https://blog.csdn.net/teleger/article/details/80893734?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522158950745419724846464939%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fall.57675%2522%257D&request_id=158950745419724846464939&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2_allfirst_rank_v2~rank_v25-1-80893734.nonecase&utm_term=%E8%A7%A3%E5%86%B3Ubuntu%E6%B2%A1%E6%9C%89%E5%A3%B0%E9%9F%B3

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Another way is, if our computer is win10, and mac, both contain Ubuntu dual system, try to open another system, then shut down, just open Ubuntu-remember to like it if you succeed.