After a bunch of messing around and with some good advice from Kacper, plus Jim Rorie's comment above, I've been able to get the subwoofer enabled on the MBP5,1 - again this was mainly Kacper's work I really just helped test it.
So Kacper has updated his patch against alsa-driver-1.0.19 to enables the subwoofer now and adds the id for the MBP5,1 so you shouldn't have to manually add model=mb5, it should now automatically be detected! I've attached the latest patch to this bug report as well. He is also going to forward the patch upstream to Alsa so it should be included in a future release - lets hope it make it into Karmic! This should hopefully resolve all the issues in this bug now. I have to say, its pretty awesome to have sound working completely now! ** Attachment added: "Patch to enable L&R speakers + subwoofer and MBP5,1 id automatically" http://launchpadlibrarian.net/26500515/alsa-driver-1.0.19-mb51.patch -- Left speaker doesn't work, controls mixed up on Apple MacBook[Pro] (5,1) https://bugs.launchpad.net/bugs/337314 You received this bug notification because you are a member of Mactel Support, which is the registrant for Mactel Support. Status in ALSA driver: Unknown Status in Mactel Support: Confirmed Status in “alsa-driver” source package in Ubuntu: New Bug description: Reporting this bug for another user... In MacBook and MacBookPro 5,1 (aluminium, late 2008) the soundcard works out of the box only with headphones, and to turn speakers on it is necessary to manually set the 6 channels. In that case, sound is heard both on headphones and right and center speaker; the left speaker doesn't work yet. This bug is confirmed by several users, see the additional information attached. de...@raker:~$ lspci | grep -i audio 00:08.0 Audio device: nVidia Corporation MCP79 High Definition Audio (rev b1) de...@raker:~$ grep Codec /proc/asound/card0/codec#* Codec: Realtek ALC889A _______________________________________________ Mailing list: https://launchpad.net/~mactel-support Post to : [email protected] Unsubscribe : https://launchpad.net/~mactel-support More help : https://help.launchpad.net/ListHelp

