Also had the same issue a few months ago. Here's how I resolved it:
https://trisquel.info/en/forum/asus-x101ch-resolution-issue-resolved-libre-linux
- [Trisquel-users] New Trisquel user having problems outp... unslaved
- Re: [Trisquel-users] New Trisquel user having prob... aliasbody
- Re: [Trisquel-users] New Trisquel user having prob... redbaptistrisquel
- Re: [Trisquel-users] New Trisquel user having prob... Michał Masłowski
- Re: [Trisquel-users] New Trisquel user having prob... unslaved
- Re: [Trisquel-users] New Trisquel user having prob... moilami
- Re: [Trisquel-users] New Trisquel user having prob... unslaved
- Re: [Trisquel-users] New Trisquel user having prob... moilami
