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Last Post 19 May 2008 11:24 PM by  birger.kroon@cybercomgroup.com
Input/output error when using /dev/dsp
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birger.kroon@cybercomgroup.com



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13 May 2008 10:59 PM
    Hi

    I receive a Input/output error when trying to play sound in any way (tested media players as well as cat to /dev/dsp). I've traced the error to the kernel driver for the PCM parts (snd_pcm_lib_write1() in sound/core/pcm_lib.c) where the code is waiting for a signal that never fires. My guess is that the signal is linked to an interrupt that never reach the driver.

    Something wierd:
    We had problems mounting the rootfs over nfs (1 out of 10 tries worked). If nfs was mounted with the tcp flag it gets very slow, but works evry time. The sound playbak works if we mount nfs w/o tcp, but w/ tcp it does not. If I mount using a SD card, the sound still does not work.

    * This seems to me as som form of resource conflict, but I have really no idea.
    * I use a i.MX31 Lite dev board from Logic
    * Tested som different kernels, but use freescale's 2.6.21.7 the most.

    -- EDIT --
    Update: The sound chip is not responding over SPI or the sound chip version number is incorrect.
    I get "PMIC not detected!!! Access Failed" from pmic_core_spi.c
    -- END EDIT --

    Has anyone seen anything like this before?
    Any input is most welcome.

    Regards
    // bikr

    Badguy



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    15 May 2008 06:04 PM
    I was able to produce this behaviour by enabling all the I2C controllers.

    two of the I2C controllers conflict with SPI

    have you enabled any of the I2C controllers?

    birger.kroon@cybercomgroup.com



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    19 May 2008 12:06 AM
    Hi

    Thanks for the suggestion. However, it did not solve the problem.

    * Has anyone experienced problems with getting the sound working on the lite kit?

    Regards
    // bikr

    birger.kroon@cybercomgroup.com



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    19 May 2008 11:24 PM
    Ok... solved I think

    Turned on the following in the kernel config:
    Device drivers -> MXC support drivers -> Advanced Power Management devices -> (all three selections enabled)

    // bikr
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