[U-Boot] [PATCH v3 1/9] Revert "pico-imx7d: Add LCD support"

Fabio Estevam festevam at gmail.com
Thu Apr 25 03:27:59 UTC 2019

Hi Jun,

On Wed, Apr 24, 2019 at 11:53 PM Jun Nie <jun.nie at linaro.org> wrote:

> It blocks boot up with default defconfig. I see it is suggested to be
> reverted in mailist weeks ago. I thought you guys knew about it.

Please keep in mind that the rationale of a patch must always be provided.

In this case the issue is related to the limit of the current that the
host PC USB port can provide.

Please see the following commit for detaisl:

commit 00102ae52055e294ac37ae1380f37620f4a8bb26
Author: Fabio Estevam <festevam at gmail.com>
Date:   Wed Mar 27 20:03:39 2019 -0300

    pico-imx7d: README: Recommend the usage of a USB hub

    Since commit 9e3c0174da842 ("pico-imx7d: Add LCD support") we started to
    notice some hangs in U-Boot.

    There is not an issue on such commit per se, but due to the LCD support
    the current drawn is increased and this may cause issues when powering
    pico-imx7d-pi from USB.

    Some computers may be a bit strict with USB current draw and will
    shut down their ports if the draw is too high.

    The solution for that is to use an externally powered USB hub between the
    board and the host computer.

    Add such recommendation to the README file.

    Signed-off-by: Fabio Estevam <festevam at gmail.com>

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