Hi, which sound card do you have? I have the 24 bit Creative Sound Blaster Live! with the
ca0106 chipset and I experience the exact same problem. Often, but not always, when I boot up
and start listening to music, regardless of the application I use, I hear no sound, or more
frequently, sound from only one channel.
I use the same technique as you to solve the problem. I start playing some music,
unplug my headphones, turn the volume all the way up and back down again, then plug my headphones
back in. When I start listening again the music is playing normally.
Sorry I don't have any other solution to this problem.
I have a dual boot system and I experience the same problem when using Windows, though not
as frequently. Oddly enough turning the volume right up and back down in Windows does not solve
the problem and I have to reboot. The fact that this behaviour occurs under both Windows XP
and Slackware Linux leads me to believe that this is a hardware problem, rather than a driver
problem, but I cannot be sure of this.
It's only a minor annoyance. Everything else about the card is great, sound quality is
excellent. Also I'd like to say thanks to the ALSA team for all the hard work they do, thanks guys.