Posts by Kor


    I read in Buildroot Release fsimx6sx-B2019.11 that there should be display support to fsimx6sx/ul.

    I tried to turn it on in U-boot config, but don't know exactly what part of configuration I should set.

    This is what I tried:

    Device drivers / Graphics support / Enable driver model support for LCD/video

    Device drivers / Graphics support / Enable legacy LCD support

    Device drivers / Graphics support / Enable video support

    But there are many errors and warnings when compiling such a configuration.

    Is LCD really supported in U-boot? If so, is there any documentation regarding LCD usage?

    Thank you,


    As we need to replace PicoCOMA5 with newer PicoCOMA9X in the existing hw, we cannot add jumpers to our board and we need to have a standard PicoCOM interface.

    We only have a few samples of PicoCOMA9X, but later when we will order more we will try to order the ones with the correct jumpers configuration.

    But now I need to change it myself - problem is that I cannot find the physical location of these jumpers in the documentation. Can you provide me with some picture or other information with their position?

    Thank you,



    I would like to clarify the question of SPI CS/MOSI swap on J1 connector.

    If I understand chapter 4.5 of document PicoCOMA9X_Hardware_en.pdf well, in older hw J1-27 was SPI_CS and J1-29 was SPI_MOSI.

    In newer hw J1-27 should be SPI_MOSI and J1-29 SPI_CS.

    I tested those pins on module Rev. 1.20 (assuming it is a newer hw) but if I set pins via /sys/class/gpio interface then changes of gpio47 can be measured on J1-29 and changes of gpio48 on J1-27.

    What is the problem? Are these J1 pins wired differently when configured as gpio or spi? Is our module (1AA4AC) really the one with fixed swap of pins?

    Thank you,



    I want to communicate with I2C device on I2C_B bus but there seems to be some confusion.

    According to PicoCOMA9X_Hardware_eng.pdf J1-30, 31 is either CAN0 or I2C0. If configured as I2C J1-30 and 31 should be SD3_DATA5 (GPIO7_IO7) and SD3_DATA7 (GPIO7_IO9):

    But in default picocoma9x.dts in pinctrl_i2c1_1 there are GPIO0_IO0 and GPIO0_IO1:


    pinctrl_i2c1_1: i2c1grp-1 {

    fsl,pins = <

    MX6SX_PAD_GPIO1_IO00__I2C1_SCL 0x4001b8b1

    MX6SX_PAD_GPIO1_IO01__I2C1_SDA 0x4001b8b1




    Which configuration is correct?

    Thank you,



    I'm trying to activate LCD support in U-Boot but when I switch on Device Drivers - Graphics support - Enable model support for LCD/video u-boot compilation crushes with multiple errors in stdio.c

    After adding obiously missing include <dm.h> some warnings are solved, but errors are still here.

    Should LCD support in u-boot work or not?

    I'm using u-boot-2018.03 from Buildroot Release (29.11.2019).

    Thank you,



    I was looking for some information about audio in PicoCOMA9X and in picocoma9x.dts I found this:

    ETH_B replaces the audio signals, so no audio is possible if ETH_B is available.

    When our PicoCOMA9X starts U-Boot prints this line:

    PicoCOMA9X Rev 1.10 (2x LAN, 1x DRAM).

    Does it mean, that there is no audio in our module? How can I found, what variant of PicoCOMA9X we exactly have?

    Can you find the variant by module's serial number 161F60?

    Thank you,



    there is some problem in sgtl5000 probe function - snd_soc_register_card fails. I turned on some I2C debug messages and here is relevant part of linux booting:

    sgtl5000 2-000a: probe

    i2c i2c-2: master_xfer[0] W, addr=0x0a, len=2

    i2c i2c-2: master_xfer[1] R, addr=0x0a, len=2

    i2c i2c-2: <i2c_imx_xfer>

    i2c i2c-2: <i2c_imx_start>

    i2c i2c-2: <i2c_imx_bus_busy>

    i2c i2c-2: <i2c_imx_xfer> transfer message: 0

    i2c i2c-2: <i2c_imx_xfer> CONTROL: IEN=1, IIEN=1, MSTA=1, MTX=1, TXAK=1, RSTA=0

    i2c i2c-2: <i2c_imx_xfer> STATUS: ICF=1, IAAS=0, IBB=1, IAL=0, SRW=0, IIF=0, RXAK=1

    i2c i2c-2: <i2c_imx_write> write slave address: addr=0x14

    i2c i2c-2: <i2c_imx_trx_complete> TRX complete

    i2c i2c-2: <i2c_imx_acked> No ACK

    i2c i2c-2: <i2c_imx_stop>

    i2c i2c-2: <i2c_imx_bus_busy>

    i2c i2c-2: <i2c_imx_xfer> exit with: error: -6

    sgtl5000 2-000a: Error reading chip id -6

    i2c-core: driver [sgtl5000] registered

    fsl-ssi-dai 2028000.ssi: No cache defaults, reading back from HW

    imx-sgtl5000 sound-sgtl5000: ASoC: CODEC DAI sgtl5000 not registered

    imx-sgtl5000 sound-sgtl5000: snd_soc_register_card failed (-517)

    Before this, the same I2C bus is used to communicate with rtc-pcf8563 and this communication seems to work.

    What should I do with this issue?



    I tried to change starx as you adviced, but there seem to be no difference in behaviour. While linux is booting, display shows tux logo, but as soon as X11 windows start display turns white and nothing else happens.

    Anyway as X11 should have been only for test purpouses, I switched to the window system we used in our former devices - Nano-X windows (via framebuffer as our module doesn't have GPU) and using this display works ok.

    So the conclusion is that I don't know why X11 doesn't work, but display interface and framebuffer are ok.

    Thanks for advices.



    I tried to change xorg.conf but X11 does't start correctly anyway.

    There is an error: Failed to open authorization file "//.serverauth.243": No such file or directory

    Complete Xorg.0.log is attached.

    Except for the changes recommended earlier in this thread, filesystem and kernel are default (fsimx6sx_std_defconfig) - created from buildroot fsimx6sx-B2019.11.

    Thank you.


    Hello again.

    Comment CONFIG_PICOCOMA9X_GPU works ok, but I am not able to see GUI in linux.

    PicoCOMA9X is in startekit equipped with 800x480 display. U-Boot works with this display without problems, I can switch U-Boot console to LCD and I see linux logo and then all the booting messages. But as soon as boot is finished, display turns off.

    Is there something else I should change in picocoma9x.dts for this PicoCOMA9X without GPU hw?



    I tryied to do it, but the compiler fails to make dtb.

    I'm not familiar with dts structure and syntax.

    1. Error: arch/arm/boot/dts/picocoma9x.dts:609.1-7 Label or path gpu3d not found
    2. FATAL ERROR: Syntax error parsing input tree


    I'm starting to use PicoCOMA9X as a replacement of PicoCOMA5 (which we are using for years). Our board is supposed to be PicoCOMA9X-V3I-LIN hw rev. 1.10.

    NBoot (VN39) and U-Boot (2018.03) are still the original ones.

    Following the documentation I uploaded to module's flash these bins (original files from VM Fedora 27 - fsmix6sx-B2019.11):




    After this upgrade and reset, linux starts to boot but it seems that it gets stuck.

    It seems that boot stops somewhere between SDHC controller and USBIFS initializations.

    In U-Boot UBIFS seems to be ok (at least ubifsmout and ls ubi 0 commands are successful) and so does SD card.

    Do you have any advice what should I try?

    All kernel messages are in attachment.

    Thank you,


    I'm developing fw on my old PicoCOMA5 and that is why I haven't noticed this "new" version until now.

    Version number is taken from NBoot:

    F&S Nand Loader VN15 built Jul 26 2019 09:29:43

    PicoCOMA5 Rev. 1.23

    Different version number is not the problem in itself. The reason why I'm checking versions is other: in this "new" board system frequency is slightly lower - 82534736 Hz while it used to be 83368421 Hz.

    This is not a big difference (about 1%) but it affects also our UART and SPI communication anyway.

    In addition, the new board also shows a kind of "jitter" when transmitting on UART/SPI - as if the new board had an unstable system frequency.

    Jitter is small, but noticeable on the oscilloscope.

    Is this also a consequence of any changes in NBoot? And is it possible to go back to some earlier version of NBoot?

    Thank you,



    we recently received new PicoCOMA5 modules with a new board revision.

    What are the differences between this new and previous revision 1.20?

    It looks like the new one uses a different crystal because the system frequency has slightly changed.

    Could you provide us with current documentation for the new board/hardware?

    Thank you,


    Is there any recommended webkit for PicoCOMA5?
    Webkit should support html+css, javascript, /dev/input interface (touchscreen) and framebuffer output.
    Thank for any suggestion.


    I am already using V2.1. Communication with RTC is not working - it seems to be problem of I2C itself. I added some debug messages and there is log:

    i2c_imx_write returns -EIO