Originally Posted by silentray
I have a question about how to re-emerge a package in Gentoo with new USEFLAG settings.
SEt the new use flags, then run "emerge -auDvN world". Everything in need of a recompilation will be emerged again.
I emerged KDE in Gentoo without the arts USEFLAG, thus my KDE sound system does not work. I have already set up ALSA and needs to re-emerge KDE with "arts" flag in.
You don't need to. In fact, I highly recommend you against doing so. Arts is crappy, tends to waste cpu uselessly, adds even more latency (not that you care about that for a desktop, but still). It adds yet another intermediate layer in top of ALSA, and gives not additional features (ALSA now enabled dmix by default, so there's no problem even if your sound chip can't do hardware mixing). Arts also has its own assort of bugs, and is completely unmaintained since years ago.
KDE can use a 3rd party program to play system sounds, if that's really that important for you. Look in the control panel, you can set an external program like mplayer, mpg123 or play to play the system sounds, no need to enable arts just for that. The rest of the stuff should work via ALSA, like it always did.