I was reading the article by Sylvia Chan, "Realism or Socialt Realism?: The "Proletarian' Episode in Modern Chinese Literatire 1927-1932"

Realism as a method, methodology --- the author tries as much as possible to avoid imparting personal emotions and feelings in his / her description of the reality. The description should be as truthful to reality as possible. Realism in this sense is both the tool and the goal.

Socialist Realism concerns primarily the ideological content of realism with which the author uses realism as a vechnical to achieve educating the readers of some prescribed ideas.

Social realism as a style prioritizes social contents as the most important aspect among other dimensions of a piece of work.

The debates revovled around contending definitions of what realism is, and whether realism is only a vechicle to achieve some larger goals.