Panel volume icon state changes to "mute" when volume reaches zero

If there is a unique state for 0% volume which isn't "mute" in the code then we only need to change the icon name for that state. If not, we need to add that state.

What is the difference between 0% volume and Mute?

The difference, as I see it, is that when you press mute at any given volume level and then un-mute it, it should go back to the level it was at when muting it originally. Currently mute=0 as far as I can tell. This means that pressing mute means literally, go to 0%. It is a fundamental difference and I think that looking at how music players, telephones and other devices work there is good reason for mute not to be 0% volume level.

Kenneth, exactly. Mute is a special state invoked by hitting a mute key. The difference between the two must be reflected with an appropriate icon.

My music player (iPod) doesn't have mute. It has a volume slider, and that's it. The only way to mute it, is to turn the volume to 0, or to pause the music.

My Alpine stereo in my truck, also does not behave this way with mute. The mute button on it, decreases the volume level to 4% of the original, and then restores it when pressed again. To get no volume, the only options are to decrease the volume by turning the knob to 0, turn the power off, or pause the music (if the source is pausable).

I think we should probably either behave like Mac OS X does here, or make the applet be astoundingly smarter, rather than exposing silly technicalities to the user, as we are currently doing now.

On my HP laptop with capacitive volume-control "softkeys", zero volume and mute are two vastly different states: hardware "mute" is indicated by the hardware mute button / LED turning orange, and mutes the internal speakers no matter what state the OS is in.

In Windows 7, the mixer offers a distinction between 0% and mute.
The volume slider ranges between 0% and 100%, indicated by the icon showing zero to three "waves".
Mute is indicated by replacing the "waves" with a circular "no" symbol, and turning the hardware Mute LED orange.

In Gnome, any time I turn down the volume with my hotkeys, I have to "dodge" the 0% mark, where gnome decides to forcibly assert the mute pin. Interestingly enough, Windows shows this same behavior only when Windows Media Center is running.

I've fiddled with the source of gnome-settings-daemon, and I found it relatively simple (aside from sign issues) to change the volume-down behavior to match the volume-up behavior, with the enhancement of not un-muting when lowering volume. Attached is a rough patch to do just that.

A marginally related bug specifically regarding HP hotkeys: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/284319

closing the bug, the current behaviour is what has been designed