UP2 console no output after commit fb4f5e727b.

[fulong82]

Describe the bug
After this commit fb4f5e727b logging: Use k_uptime_get_32 for high frequency system clock
and build Zephyr for up squared board with the default configs + CONFIG_SHELL:
1.) https://github.com/zephyrproject-rtos/zephyr/blob/master/boards/x86/up_squared/up_squared_defconfig#L4
2.) https://github.com/zephyrproject-rtos/zephyr/blob/master/drivers/timer/Kconfig#L19
3.) https://github.com/zephyrproject-rtos/zephyr/blob/master/kernel/Kconfig#L754
There is no console output from UART port 0.

To Reproduce
Steps to reproduce the behavior:

1. mkdir build; cd build
2. cmake -DBOARD=up_squared ../
3. make menuconfig & select CONFIG_SHELL
4. make
5. Boot up and wait for console output

Expected behavior
Console shell is able to show up on UART port 0 and user able to interact with Zephyr through the shell terminal.

Impact
User unable to interact with Zephyr shell terminal.

Screenshots or console output

Environment (please complete the following information):

• OS: Ubuntu 14.04
• Toolchain: Zephyr SDK 0.9.5
• Commit: 96235c5

Additional context
To workaround this issue, we could compile with CONFIG_TICKLESS_KERNEL=n

[dcpleung]

I tried commit 2320973 using samples/subsys/shell/shell_module on the UP Squared board and it worked fine without any issue.

Did you update the BIOS? If so, the MMIO addresses might have changed. Do you have CONFIG_PCI and CONFIG_PCI_ENUMERATION turned on? Zephyr will probe for address and IRQ if they are both turned on.

[fulong82]

Hi,

I test using samples/hello_world/ and here i attached my config file for your debugging reference:-
Not working config: up2_no_console_config.txt
Workaround config that able to see console: up2_wa_console_output_config.txt
w/ the workaround below is the console output screenshot:

Thanks & Regards,
Wilson

[fulong82]

Hi,

I do not know which BIOS version you are referring, below screenshot is the BIOS i am using:

Thanks & Regards,
Wilson

[dcpleung]

I tried cherry-picking config options from the your uploaded files. The issue is actually an chicken-or-egg problem. When CONFIG_PCI_ENUMERATION=y and CONFIG_PCI_LOG_LEVEL_DBG=y are both enabled, the NS16550 UART driver is not initialized by default. However, during device scans, the PCI driver is trying to output through UART. And it caused an exception. To workaround this, find the actual MMIO address for the UARTs, and set CONFIG_UART_NS16550_PCI=n.

Not an actual bug on UP2. So close this one and opening another one on logging...