#6933 LOW Never A: hardwaremanager.py sometimes sees zero audio volumes

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#6933: hardwaremanager.py sometimes sees zero audio volumes
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 Reporter:  mtd     |       Owner:  mtd           
     Type:  defect  |      Status:  new           
 Priority:  low     |   Milestone:  Never Assigned
Component:  sugar   |     Version:                
 Keywords:          |    Verified:  0             
 Blocking:          |   Blockedby:                
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 hardwaremanager.py sometimes sees zero channel volumes from
 gst.element_factory_make('alsamixer')'s master device.

 This appears to be a bug in either gst or alsa, as alsamixer shows non-
 zero channel values.

 To reproduce:

 1) viewable from another display device, ssh in to an XO running Sugar and
 run alsamixer
 2a) on the XO running sugar, activate the frame, go to the speaker device,
 and click once on the volume slider
 2b) Optionally, add the following to hardwaremanager.py's get_volume
 method at the sensible place (currently line 74 in hardwaremanager.py):
 {{{
 if 0 in volumes:
     import logging
     logging.debug("got zero value from gst/alsa: %s" % volumes)
 }}}
 3) Hold down the left or right arrow key, arbitrarily
 4) Observe alsamixer's master volume

 During 4), one will observe the left channel (almost always) flickering to
 zero and back again (as hardwaremanager.py compensates for this bug).

 If one has done 2b), one will observe the zero return values more
 obviously.

 Expected behavior:  no flickering should be observed.  Volume reported by
 gst/alsa should never be zero for a channel unless the channel's volume is
 actually zero.

 This bug should become a tracker for an upstream bug once such an upstream
 bug has been filed.

-- 
Ticket URL: <http://dev.laptop.org/ticket/6933>
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