Red Hat Bugzilla – Bug 173250
headphones work, built-in speakers do not
Last modified: 2007-11-30 17:11:17 EST
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20050922 Fedora/1.0.7-1.1.fc4 Firefox/1.0.7 Description of problem: Installing FC4 on a Dell Latitude D600 laptop. After installation, no sound comes from speakers. Sound does come from headphones. Ran 'yum update' to get all the latest packages ... no difference in behavior. Other people report similiar issues on other hardware. One can fix this problem using alsamixer ... but the config needs to be repaired so that it is configured to work properly after a clean installation. I apologize if this is a duplicate bug. I searched through bugzilla and could not find it. Similar bugs seemed: 156575 154080 169729 Version-Release number of selected component (if applicable): alsa-utils-1.0.9rf-2.FC4 How reproducible: Always Steps to Reproduce: 1. Install FC4 on some (many?) laptops with built-in speakers 2. test the sound card using system-config-soundcard 3. observe that there is no sound 4. plug in headphones and hear the sound Actual Results: Sound comes only from headphones Expected Results: sound also comes from speakers Additional info: This email thread discusses this issue: https://www.redhat.com/archives/fedora-list/2005-June/msg03316.html It tells one to use 'alsa-mixer' to enable 'External Amplifier'. It worked for me, but I don't really understand it. I could find no references in bugzilla that this was actually fixed. The configuration should be fixed so that the speaker functions properly after a normal installation.
Unfortunately this switch depends on your HW. Some machines need it OFF and some machines need it ON. There isn't any way how to determine the right state for your machine (at least I don't know how to do it) so you have to check it. Upstream works on this issue....
> Some machines need it OFF and some machines need it ON. Hmmm ... that seems strange to me ... but you are the expert. Q: What do you mean by 'Upstream works on this issue ...'
> Some machines need it OFF and some machines need it ON. Q: What is the behavior if it is in the wrong state? Q: Is it the case that some sound hardware needs it OFF to make sound while other sound hardware needs it ON to make sound? Q: Is there any other undesirable behavior (like crashing) if the setting is wrong? If having the setting in the wrong state does not do anything particularly bad, then I recommend an enhancement to 'system-config-sound' so that one can control the state of this switch from that control panel. I suspect that most people on RedHat/Fedora systems would go there first. We could add a checkbox to control this 'External Amplifier' setting ... rather than doing nothing and leaving people to figure it out on their own.
People around the ALSA project (www.alsa-project.org) prepare the new mixer interface which should fix this problem. The problem is the soundcard has typicaly many outputs and it depends on designer of your HW which output is connected to headphone, which to "speakers" and so on... The "External Amplifier" can mean (I only guess) that your card has some external device to adjust volume for speakers. If the settings are wrong you don't hear the sound because the channel which is connected to your output device is suspended. It doesn't have any side effects, you only hear nothing.
OK ... thanks for the followup. I now understand. I have submitted a bug with alsa-project.org and will work with them.
The bug I submitted at alsa-project is: https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1564