I’ve recently been using Openbox on Ubuntu on my Thinkpad T440s and wanted to use Volti as my volume control with a Tint2 panel. I had trouble though, I was getting this error:
[alsactrl.py:__init__:41] can’t open Master control for card HDMI, trying to select first available mixer channel
[alsactrl.py:__init__:49] can’t open first available control for card HDMI
error: list index out of range
Traceback (most recent call last):
File “/usr/bin/volti”, line 53, in <module>
volti = main.VolumeTray()
File “/usr/lib/volti/volti/main.py”, line 124, in __init__
self.watchid = gobject.io_add_watch(fd, eventmask, self.update)
TypeError: an integer is required
The solution lies in the Volti configuration file. It is located at ~/.config/volti/config.
In my case, the issue was with the third line under [global], the card index value. My default card_index was 0. Changing this to 1 and saving the file fixed the issue.