Actually it's always the same error. The message just appears in that file multiple times for different hardware generations.
Which is fine, presupposing that the user already knows what hardware generation they are using _and_ how the video card manufacturer actually implemented the display interfaces, as, for instance, whether or not the "external PLL" really exists, or was left off. That is "presuming the conclusion", though. The user does _not_ know.
The problem is that the error message is not informative for the person who is actually encountering the problem. At that point, the user already knows that their display is not working, and they do not need an error message that says, effectively, "Your display is not working." That is insulting. They need information about how to respond, how to "fix" the problem. The idea is to be able to look at the source code.
For instance, I have an HD 5570 card, including a DisplayPort interface, for which we can read "The 5000-series designs host two internal clocks and one external clock." With exactly three clocks and three displays, there should _never_ be an allocation error. Instead, there are constant "unable to allocate a PPLL" errors, generated in the fifth "/* all other cases */" code path. Why?
I had to modify and recompile the source just to find where the error was being generated. Please make life a little easier.
James