ALSA Tray cannot handle an ALSA card which has no mixers

[Philipp Millar]

Everytime I try to start alsa-tray I get this traceback:

Traceback (most recent call last):
  File "/usr/bin/alsa-tray", line 824, in <module>
    ls_cards_mixers()
  File "/usr/bin/alsa-tray", line 687, in ls_cards_mixers
    for mixer_name in alsaaudio.mixers(CARD_LIST.index(card_name)):
alsaaudio.ALSAAudioError: No such file or directory

It seems this is a problem where one card has no mixer as in https://code.google.com/p/volti/issues/detail?id=27
Here's the python dump from the mentioned bugreport for my system

>>> import alsaaudio as alsa

>>> alsa.cards()
[u'PCH', u'ThinkPadEC']

>>> alsa.mixers()
[u'Master', u'Headphone', u'Speaker', u'PCM', u'Mic Boost', u'IEC958', u'IEC958', u'IEC958', u'Beep', u'Capture', u'Auto-Mute Mode', u'Digital', u'Internal Mic Boost']

>>> alsa.mixers(1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
alsaaudio.ALSAAudioError: No such file or directory

Volti seems to have this issue resolved with tis patch https://code.google.com/p/volti/issues/attachmentText?id=27&aid=-6066430469773631935&name=volti-0.2.3_card-without-mixer.patch