display broken character on shift_jis encoding

[li1.lin]

Because display broken characters when diff the shift_jis encoding file by default.
I configed the .gitattributes for that.
After that It can resovled the diff problem before commit.

But still have some problems
  1.display a file before add to index

     

  2.diff in history after commit

    

Please give me some info to resolve this problem.
Thanks!