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Last Post 30 May 2018 06:54 AM by  adam.ford@logicpd.com
DM37 Audio on Modern (4.4+) Kernels
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adam.ford@logicpd.com
Advanced Member
Advanced Member
Posts:783


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03 Feb 2018 09:24 AM

    The Audio on the baseboard is routed through the twl4030 PMIC.

     

    When the audio driver is loaded 'omap-twl4030 sound: twl4030-hifi <-> 49022000.mcbsp mapping ok' should appear in dmesg.

     

    In order to use the audio, the alsa packages need to be installed.

    From the buildroot directory: type make menuconfig

    Target Packages - > Audio and Video Applications -> alsa-utils

    Leave the default options selected and add alsamixer, aplay and speaker test

     

    Build (make) buildroot with the new packages and install.

    Boot the board with the new files added.

    By default, the audio device is muted.

    run alsamixer and locate Headset L1 and Headset R1 and unmute both by selecting each and pressing the 'm' button

    Adjust DCA2 Analog to approximately 50 and DAC2 Digital Fine between 50-75 and Headset to about 67.  These settings can be adjusted for personal preference.

    Exit the mixer

    Connect headphones to the Line Out jack on the basebase

    Run the speaker test to hear the audio.

    speaker-test -t wave -c2

    -t wave will play a voice indicating which channel is playing

    -c2 will specify stereo (ie, front left, front right)

     

    mfonseca@keywcorp.com
    New Member
    New Member
    Posts:15


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    08 May 2018 02:21 PM

    Hi Adam,

     

    Have you seen any errors like "omap-mcbsp 49022000.mcbsp: TX Buffer Overflow!" when playing audio?  I'm seeing these during audio playback on a 4.9.x kernel.

     

    Thanks,

    Marco Fonseca

    bradb@logicpd.com
    Basic Member
    Basic Member
    Posts:200


    --
    08 May 2018 02:38 PM

    Marco,

    I did not see that error when testing the audio using the 4.9.89 kernel.  We just released the user's guide, release notes,  and SD image to the Product Webpages.  The VM is currently being uploaded now. 

    If you are still having trouble, please provide us the steps to duplicate your issue and the audio file at platformsupport@logicpd.com.

    Thanks,

    Brad

    mfonseca@keywcorp.com
    New Member
    New Member
    Posts:15


    --
    09 May 2018 08:31 AM

    Hi Brad,

    If I'm runing a 4.9.94 kernel.  Are there any additonal patches not commited upstream that I would need to be up to date with logicpd's changes?

    Thanks,

    Marco Fonseca

    adam.ford@logicpd.com
    Advanced Member
    Advanced Member
    Posts:783


    --
    09 May 2018 08:50 AM
    You should not need any extra patches for the Torpedo. The SOM-LV needs some patching for its mute pin. However, the audio is muted by default, so the user guide instructs you on how to un-mute the audio to make the sound work.

    I've only tested the Torpedo using the speaker-test -c2 -t wave function, so it just says 'front left...front right' over and over again.

    I am not sure if Brad has tested with music or extended audio stuff.

    adam
    mfonseca@keywcorp.com
    New Member
    New Member
    Posts:15


    --
    25 May 2018 03:39 PM

    It was a big pain to figure out but you will get 

        omap-mcbsp 49022000.mcbsp: TX Buffer Overflow!

    if you don't load some of the video for linux kernel modules.

    I needed to additionally load these other mods:

    omap3_isp 95568 0 - Live 0xbf27e000
    videobuf2_v4l2 10344 1 omap3_isp, Live 0xbf276000
    videobuf2_core 24781 2 omap3_isp,videobuf2_v4l2, Live 0xbf249000
    videobuf2_dma_contig 8715 1 omap3_isp, Live 0xbf221000
    videobuf2_memops 1140 1 videobuf2_dma_contig, Live 0xbf1f4000

    I can then leave them loaded, or rmmod them, and it will work from there.  So I assume there is a
    configuration/initialization problem with the OMAP sound drivers, that videoforlinux subsystem gets
    right...?

     

    Thanks,

    Marco Fonseca

    adam.ford@logicpd.com
    Advanced Member
    Advanced Member
    Posts:783


    --
    30 May 2018 06:54 AM
    I am not sure why Video For Linux would be required. Several of us have used the audio, I'll dig through some of my e-mails from the Linux community to see what, if anything I can find.

    adam
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