eMMC and buildroot - ACPI mode not detected

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sivizue
sivizue New Member Posts: 3

Hello,

I tried to use the eMMC with the latest stable buildroot (kernel 4.19) but the eMMC was not detected (I enabled the SDHCI_ACPI option).

I finally managed to use it by swithing the mode to PCI in the BIOS.

So I have a few questions:

  • Is ACPI a better mode? If so, why? (I didn't find anything relevant for now).

BTW, if someone managed to enable the eMMC detection with ACPI mode, I would be please to know what I missed on the kernel configuration :)

Comments

  • ccalde
    ccalde New Member Posts: 348 ✭✭✭
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    Hi @sivizue ,

    The only one kernel supported by our team is the kernel 4.15:
    https://wiki.up-community.org/Ubuntu

    It is supported for Ubuntu 16.04 and Ubuntu 18.04 as well.
    Please, confirm you are able to install the supported Ubuntu + kernel in your UP board.

  • sivizue
    sivizue New Member Posts: 3
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    Hi,

    The board is working like a charm with both Ubuntu 16.04, Ubuntu 18.04 and Debian buster (testing). I already try the 4.14 and 4.15 version, but I get the same behavior. I suspect that another option shall be enabled to detect the eMMC in ACPI mode properly, but I can figure out which one.

    BTW, it is also working properly with buildroot if the eMMC is configured in PCI mode in the BIOS (hence my question ACPI vs PCI) :)

  • ccalde
    ccalde New Member Posts: 348 ✭✭✭
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    Hi @sivizue ,

    For ACPI option, I think kernel configuration is necessary as well.

    You said, you get CONFIG_MMC_SDHCI_ACPI enable, right?
    That configurations depends on CONFIG_MMC_SDHCI && CONFIG_ACPI && CONFIG_PCI. Did you enable them for your kernel?

  • sivizue
    sivizue New Member Posts: 3
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    Hi,

    Theses configurations are enabled (in fact, I don't think that it is possible to enable MMC_SDHC_ACPI without the others).

    Anyway, thank you for your help :smile:

  • ccalde
    ccalde New Member Posts: 348 ✭✭✭
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    Hi @sivizue ,

    If the MMC controller is configured in ACPI mode in the BIOS, then you should see the ACPI directory here:
    cat /sys/bus/acpi/devices/80860F14:00/status

    That is the first test to be sure the ACPI mode is set correctly via BIOS settings.
    Could you please confirm that to me?

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