Random hangs on boot time with BSP FSL 1046a when accessed via a serial port

[javier_tia]

Hi,

Booting a BSP FSL 1046a, it's randomly getting hanged when it's been accessed via a serial port. If any key it's pressed, the board continues booting just fine. What could it be done to avoid the random hangs?

Yocto v3.0 (Zeus)
Linux kernel v4.19.68 
systemd v243 LSDK 
Tag LSDK-19.09-update-291119-V4.19

I could provide more information if it's needed. I really appreciate any help that you can provide,
Javier

edit: I found out this post should be in QorIQ Processing Platforms. I don't have permission to move the post to that forum.

[javier_tia · Accepted solution]

Workaround to solve it is disabling the kernel and systemd logging. Too much logging under telnet produces a random hang.

[yipingwang]

I generated  Yocto 3.0 image kernel-fsl-ls1046ardb.itb, and verified it on LS1046ARDB demo board, didn't reproduce your problem.

I uploaded my image in the following link.

https://drive.google.com/file/d/1MW0G6HBdaxtKFk9vqMCitV7Yq-sLnUH3/view?usp=sharing

Please try my image on your target board to check whether this problem still can be reproduced.

=> tftp 0xa0000000 b25805/ls1046ardb/kernel-fsl-ls1046ardb.itb

=> bootm 0xa0000000

[javier_tia]

@yipingwang hi, we found how serial port it's getting hanged when the serial port is stressed with many characters, like logs. This was not happening before with Linux kernel v4.14. Is there a way to tweak the serial Linux kernel module/driver to avoid the hang when it's stressed?

[yipingwang]

Please try whether this problem can be reproduced with my Image provided previously.

 In addition, please check Linux Kernel configuration file whether Serial drivers is configured as the following.

#
# Serial drivers
#
CONFIG_SERIAL_EARLYCON=y
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_DEPRECATED_OPTIONS=y
CONFIG_SERIAL_8250_PNP=y
# CONFIG_SERIAL_8250_FINTEK is not set
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_SERIAL_8250_DMA=y
CONFIG_SERIAL_8250_PCI=y
CONFIG_SERIAL_8250_EXAR=y
CONFIG_SERIAL_8250_NR_UARTS=4
CONFIG_SERIAL_8250_RUNTIME_UARTS=4
CONFIG_SERIAL_8250_EXTENDED=y
# CONFIG_SERIAL_8250_MANY_PORTS is not set
# CONFIG_SERIAL_8250_ASPEED_VUART is not set
CONFIG_SERIAL_8250_SHARE_IRQ=y
# CONFIG_SERIAL_8250_DETECT_IRQ is not set
# CONFIG_SERIAL_8250_RSA is not set
CONFIG_SERIAL_8250_DWLIB=y
CONFIG_SERIAL_8250_BCM2835AUX=y
CONFIG_SERIAL_8250_FSL=y
CONFIG_SERIAL_8250_DW=y
# CONFIG_SERIAL_8250_RT288X is not set
CONFIG_SERIAL_8250_OMAP=y
CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP=y

CONFIG_SERIAL_8250_MT6577=y
CONFIG_SERIAL_8250_UNIPHIER=y
CONFIG_SERIAL_OF_PLATFORM=y

#
# Non-8250 serial port support
#
# CONFIG_SERIAL_AMBA_PL010 is not set
CONFIG_SERIAL_AMBA_PL011=y
CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
# CONFIG_SERIAL_EARLYCON_ARM_SEMIHOST is not set
CONFIG_SERIAL_MESON=y
CONFIG_SERIAL_MESON_CONSOLE=y
CONFIG_SERIAL_SAMSUNG=y
CONFIG_SERIAL_SAMSUNG_UARTS_4=y
CONFIG_SERIAL_SAMSUNG_UARTS=4
CONFIG_SERIAL_SAMSUNG_CONSOLE=y
CONFIG_SERIAL_TEGRA=y
CONFIG_SERIAL_TEGRA_TCU=y
CONFIG_SERIAL_TEGRA_TCU_CONSOLE=y
# CONFIG_SERIAL_MAX3100 is not set
# CONFIG_SERIAL_MAX310X is not set
CONFIG_SERIAL_IMX=y
CONFIG_SERIAL_IMX_CONSOLE=y
# CONFIG_SERIAL_UARTLITE is not set
CONFIG_SERIAL_SH_SCI=y
CONFIG_SERIAL_SH_SCI_NR_UARTS=18
CONFIG_SERIAL_SH_SCI_CONSOLE=y

CONFIG_SERIAL_SH_SCI_EARLYCON=y
CONFIG_SERIAL_SH_SCI_DMA=y
CONFIG_SERIAL_CORE=y
CONFIG_SERIAL_CORE_CONSOLE=y
# CONFIG_SERIAL_JSM is not set
CONFIG_SERIAL_MSM=y
CONFIG_SERIAL_MSM_CONSOLE=y
CONFIG_SERIAL_QCOM_GENI=y
CONFIG_SERIAL_QCOM_GENI_CONSOLE=y
# CONFIG_SERIAL_SIFIVE is not set
# CONFIG_SERIAL_SCCNXP is not set
# CONFIG_SERIAL_SC16IS7XX is not set
# CONFIG_SERIAL_ALTERA_JTAGUART is not set
# CONFIG_SERIAL_ALTERA_UART is not set
# CONFIG_SERIAL_IFX6X60 is not set
CONFIG_SERIAL_XILINX_PS_UART=y
CONFIG_SERIAL_XILINX_PS_UART_CONSOLE=y
# CONFIG_SERIAL_ARC is not set
# CONFIG_SERIAL_RP2 is not set
CONFIG_SERIAL_FSL_LPUART=y
CONFIG_SERIAL_FSL_LPUART_CONSOLE=y
CONFIG_SERIAL_FSL_LINFLEXUART=y
CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE=y
# CONFIG_SERIAL_CONEXANT_DIGICOLOR is not set
# CONFIG_SERIAL_SPRD is not set
CONFIG_SERIAL_MVEBU_UART=y
CONFIG_SERIAL_MVEBU_CONSOLE=y
# end of Serial drivers