V るにはVた (VにはVだ）ends in a negative experience although you did it, hoping to end in a positive experience. 読むには読んだが、よく理解できなかった。In this sentence, what you did was that you read it and the negative experience is that you couldn't understand it.
Here are a couple of more examples: この薬を飲むには飲んだけど、あまり効き目がなかった。(I took this medicine, but it was not that effective), そこに行くには行ったけど、山田さんはいなかった。(I went there, but Mr. Yamada was not there.), その映画を見るには見たけど、あまり面白くなかった。(I watched the movie, but it was not that interesting.)
The underlined parts above are what you did hoping that you would end in a positive experience and the bolded parts are the negative experiences you had instead. I hope this helps.