I’m not exactly sure if this is in the right place; I apologize if it isn’t. For some reason, when I plug headphones into my computer, sound comes out through both the headphones and the computer’s speakers. Is there a way to disable the speakers when headphone are plugged in, or even disable them altogether?
This reads like a bug. What openSUSE version are you using? If you are using an older (pre-openSUSE-11.3) version, then maybe its been fixed. If not, then maybe it still needs to be fixed.
If you are using 11.3, then probably the quickest way to get this fixed is to write a bug report on openSUSE-11.3 component sound, with guidance here for raising a bug report: openSUSE:Submitting bug reports - openSUSE Use your openSUSE forums username and password when logging on to the Novell bugzilla. Attach to your bug report the /tmp/alsa-info.txt file created by running:
/usr/sbin/alsa-info.sh --no-upload
That will get the immediate attention of the SuSE-GmbH sound packager, who is also an alsa sound driver developer. If anyone can sort this, he can! Note he will NOT read a forum thread, so you need to ensure your bug report has all the salient information.
If you wish us to look at this further on the forum, you need to provide the information recommended to be provided as noted in the 2nd half of the multimedia stickie: Welcome to multimedia sub-area
… but my experience wrt the problem you report, is all that I will be able to recommend is to update alsa (guidance here: SDB:Alsa-update - openSUSE ) and in fact, a quicker approach is likely to get the SuSE-GmbH packagers attention via a bug report.
Good luck !