The 21-year-old left-back or centre-back has moved to the Championship side,now managed by Scott Parker.
Six of the Newcastle-born player's 15 appearances for the Whites came last season, the last of them his start in the FA Cup third-round defeat at Crawley Town. His only Premier League outings were as a substitute against Manchester United and City.
He was part of the Leeds squad which won the Division 2 title in their first season in Premier League 2 last term.
The only new senior player Leeds have signed this summer is left-back Junior Firpo, and the facility within the deal to make it permanent suggests this is more about the youngster gaining experience.
The move appeared to have foundered earlier this month, but Bournemouth have now pushed it through.
A product of the famous Wallsend Boys Club, Davis joined Leeds from Morecambe in 2018, and he made his senior debut at Villa Park at the end of that year but knee surgery ended his campaign early.
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