I recently purchased a Huawei Matebook X Pro and after installing a fresh copy of Fedora I noticed 2 of the 4 speakers were muted. I have some information and a fix I'll post in another comment. Uploaded my alsa info to the project site: http://www.alsa-project.org/db/?f=cc31c445483eb865bebc193fbf694c76059c3ca5
I stumbled on an old ticket for the previous version of this laptop, https://bugzilla.kernel.org/show_bug.cgi?id=197801.
I also found a forum post with a fix for a similar laptop, the magicbook (Maybe asia equivalent of the matebook x?): https://club.huawei.com/thread-15777850-1-1.html
So after applying a similar fix to my laptop I got the other two speakers working using these steps:
1. dnf install alsa-tools
3. Choose the codec Realtek ALC256
4. Turn on option "Show unconnected pins"
5. Turn on option "Advanced override" (Couldn't get the sound playing without this)
6. Hit Override on Pin ID 0x14
7. Put in these options below it:
- Connectivity: Don't touch, leave blank
- Location: Internal
- Device: Speaker
- Jack: Other Analog
- Color: Unknown
- Jack detection: Not present
- Channel group: 1
- Channel (in group): Front
8. Click Apply now and test.
9. If it worked hit "Install boot override"
Found a slightly better setup that lets you use 4.0 sound: https://imgur.com/a/N1xsCVZ, the 0x14 speakers are a bit quiet though not sure how to improve that.