MacBook Pro - MBP: Line-In/Mic/Headset behavior changed during 10.4 release

Hi folks,

I have a problem with my headset and the line-in of my MBP C2D.
Well I know it's a line-in instead of mic-in and you can read it on the apple forums that you need a USB or Bluetooth headset for example and a normal headset mic will not work.

But there are several things that make no sense:

- MBP and MP have the same line-in. The same headset is working at the MB but not at my MBP
- My headset worked in an early 10.4 release, after some later update it stopped working (this experience is the same as for other users I found in the apple forums)
- firmware upgrade and leopard hadn't any effect

Apperently the behaviour of the line-in was changed on a software base during the 10.4 release period. This brings to the question if it's not possible to change it back.

- the build-in mic works fine for skype etc. but it's not flexible and you have to talk into a specific direction what sucks.
- having a usb headset on a book with 2x usb connectors isn't good as well

To open a call at Apple doesn't make sense either as it's basically a by design issue which will be refussed to be logged as a new case.

but:
- it worked before (so no limitation of the hardware or failure)
- it works at the MB very well


I've spent several ours on that issue but had no luck in finding anything usefull. Maybe someone here in this forum has a hint how to solve the problem as it's most probably software based. Maybe just running the line-in with differnt spec..


Thanks for now at least for reading.. :-)

Cheers,
David