touch-packages team mailing list archive

[David Chatterton <dmchatterton@xxxxxxxxxx>]

I am attempting to eliminate possible poor electrical connections
associated with the headphone socket by starting up the laptop from cold
(literally having cooled down) and running a video to check the sound
quality.

Last evening, within 10 minutes of starting the laptop from cold, the
sound became crackly. I used the Test Sound button on the Sound panel
and found no response from the Front Left Test button. However, the
Front Right Test button caused a muted response from the left speaker! I
did an immediated restart and everything then worked perfectly - no
crackles and correct sound tests.

This morning, after an overnight cold soak, the system started up and
the speakers responded correctly to the Test Sound button. However,
within 10 minutes of playing a video, the sound became crackly. The
speakers responded correctly to the test Sound button and the crackles
subsided. I plugged in a pair of headphones which caused the device
identification panel (headphones, headset or microphone) to pop up.
However, the sound was directed through the headphone straight away. On
removing the headphones, the sound went back to the speakers without
having to click their menu item in the Sound panel. (Has the system
"learned" from previous connections?)

After a further 20 minutes of playing the video, the sound became
crackly again. The speakers did respond correctly to the Test Sound
button but the crackles were still evident. I picked up the laptop and
gently tapped the underside of the case near the headphone socket. This
might have contributed to the crackling sound but it then disappeared
and the speakers sounded normal again.

By this time, the laptop had warmed up to its normal operating
temperature.

Since plugging in headphones seems to cause an interrupt that brings up
the device select panel, there must be an electrical interface between
the headphone socket and the circuit board. I doubt if the headphone
socket is gold plated but intermittent connection must be expected with
such an interface. Normally, when there is a connection between
mechanical contacts and electronic circuits, some form of bounce
suppression is employed. Apart from the early electronic calculators
that used mercury wetted reed switches, it has been common practice to
include this bounce suppression in the software. I am sure that this has
not been overlooked in the Linux kernel but it might be prudent to
ensure that such a bounce suppression is compatible with the cheap and
chearful electrical contacts found on headphone sockets. (Software bouce
suppression works well enough on keyboards. Perhaps the parameters used
could be migrated to the headphone socket interface.)

-- 
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to alsa-driver in Ubuntu.
https://bugs.launchpad.net/bugs/1402666

Title:
  [XPS13 9333, Intel Haswell HDMI, Digital Out, HDMI] Playback problem

Status in alsa-driver package in Ubuntu:
  Incomplete

Bug description:
  If an HDMI monitor is plugged into the video out and the Videos app is
  started, the Systems Settings > Sound > Output shows only the
  Speakers, Built-in Audio in the Play sound through listing. The HDMI
  option is not presented.

  The workaround is to open the VLC app which lists the Built-in Stereo (HDMI) option under its Audio > Audio Devices menu.
   
  When a video is started in VLC, having selected the HDMI option, the sound plays through the monitor speakers. The HDMI / Display Port , Built-in Audio item then appears in the Play sound through window, even though the selection highlight remains on Speakers. The sound output can be switched between either output by highlighting the chosen option.

  If VLC is closed and Videos is restarted, the sound now plays through
  the previously selected HDMI item and can be switched between the
  monitor and the laptop's speakers.

  What I regard as a bug is the failure of the HDMI option to appear in
  the Play sound through listing as soon as an HDMI monitor is plugged
  into the Display Port output. Obviously, VLC has the means to add this
  item but the Videos app does not seem to be able to do this by itself.

  In contrast, as soon as a previously paired set of Bluetooth headphone
  are turned on, the Headset does appear as a menu item in the listing.
  I would reasonably expect the plugging in of an HDMI monitor into the
  Display Port to automatically add this item as well as its affects on
  the Screen Display pane of Systems Settings.

  Note: the laptop is running Ubuntu 14.10 and the Linux kernel has
  recently been upgraded to v3.18 (Vivid).

  ProblemType: Bug
  DistroRelease: Ubuntu 14.10
  Package: alsa-base 1.0.25+dfsg-0ubuntu4
  Uname: Linux 3.18.0-031800-generic x86_64
  ApportVersion: 2.14.7-0ubuntu8
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/pcmC1D0c:   david      2242 F...m pulseaudio
   /dev/snd/controlC1:  david      2242 F.... pulseaudio
   /dev/snd/controlC0:  david      2242 F.... pulseaudio
  CurrentDesktop: Unity
  Date: Mon Dec 15 13:13:47 2014
  InstallationDate: Installed on 2014-12-11 (3 days ago)
  InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
  PackageArchitecture: all
  ProcEnviron:
   LANGUAGE=en_GB:en
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_GB.UTF-8
   SHELL=/bin/bash
  SourcePackage: alsa-driver
  Symptom: audio
  Symptom_AlsaPlaybackTest: ALSA playback test through plughw:HDMI failed
  Symptom_Card: Built-in Audio - HDA Intel HDMI
  Symptom_Jack: Digital Out, HDMI
  Symptom_Type: None of the above
  Title: [XPS13 9333, Intel Haswell HDMI, Digital Out, HDMI] Playback problem
  UpgradeStatus: Upgraded to utopic on 2014-12-11 (3 days ago)
  dmi.bios.date: 09/11/2014
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: A05
  dmi.board.name: 0D13CR
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A00
  dmi.chassis.type: 8
  dmi.chassis.vendor: Dell Inc.
  dmi.chassis.version: 0.1
  dmi.modalias: dmi:bvnDellInc.:bvrA05:bd09/11/2014:svnDellInc.:pnXPS139333:pvr:rvnDellInc.:rn0D13CR:rvrA00:cvnDellInc.:ct8:cvr0.1:
  dmi.product.name: XPS13 9333
  dmi.sys.vendor: Dell Inc.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1402666/+subscriptions