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Kernel debug. Using the UART
#11
OK, anyway I feel comfortable with UART4.
So, by any chance is it possible to change the setting after boot, whether I need UART2?
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#12
Hi,

Could you provide your "/boot/hw_intf.conf" for us checking?
Thanks.
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#13
Code:
$  cat /boot/hw_intf.conf

#Hardware Interface Config

intf:spi0=off
intf:uart2=on
intf:uart3=on
intf:uart4=on
intf:pcm_i2s=on
intf:i2c1=on
intf:i2c4=on
intf:spi2=on
intf:pwm2=on
intf:pwm3=on
intf:uart1=on

#DTS Overlay Config
# 1. check the name.dtbo in /boot/overlays
# 2. add intf:dtoverlay=name as below

#intf:dtoverlay=i2c
I've change UART2, but it doesn't change. Perhaps I should turn pwm2 off
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#14
(08-07-2018, 07:18 AM)Im4Tinker Wrote:
Code:
$  cat /boot/hw_intf.conf

#Hardware Interface Config

intf:spi0=off
intf:uart2=on
intf:uart3=on
intf:uart4=on
intf:pcm_i2s=on
intf:i2c1=on
intf:i2c4=on
intf:spi2=on
intf:pwm2=on
intf:pwm3=on
intf:uart1=on

#DTS Overlay Config
# 1. check the name.dtbo in /boot/overlays
# 2. add intf:dtoverlay=name as below

#intf:dtoverlay=i2c
I've change UART2, but it doesn't change. Perhaps I should turn pwm2 off

Hi,

Yes, because the PWM2 & PWM3 are using the same pins as UART2's (multi-function).
And because in the setting table, PWM is takes precedence over UART.
So you need to turn PWM as off.

Please take a try again.
Thanks.
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#15
OK, that's fine.
Is it possible to modify these setting without rebooting ?
I suspect that the kernel will get confused, whether we try a change on the setting.
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#16
I'm back to this thread.
I got the USB converter working, I'm now looking to carry out a debug.
I exclude quiet from the kernel command line to see more information. But there aren't chances to stop, nor to proceed interactively.
Is there a chance to set u-boot to start with interaction and add a debug option to that ?

I'd like to try my own kernel and, perhaps, u-boot, but right now I miss many information how to check the boot process.

I only found pre-canned set up. I'm willing to learn, but there are to many information that are not so useful.
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#17
Hi Im4Tinker

Is there a chance to set u-boot to start with interaction and add a debug option to that ?
-->try to set "CONFIG_BOOTDELAY" to n at [source code]/configs/tinker-rk3288_defconfig. it just set the autoboot countdown to n seconds on startup of uboot.
....rebuilt uboot and reflash it.

i am not expert in booting process,
...as i know it just as bleow:
MASROM --> SPL --> uboot --> kernel --> rootfs
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#18
Thank you for the point. Meanwhile we (my friend and I) had a progress to start the u-boot.

So I got the interactive shell. Need some learning to proceed with the instructions to boot the rootfs.
I still have a lot to learn about customization and boot sequence. It's my wish to set the options by extlinux.conf.
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#19
(08-16-2018, 02:18 PM)Im4Tinker Wrote: Thank you for the point. Meanwhile we (my friend and I) had a progress to start the u-boot.

So I got the interactive shell. Need some learning to proceed with the instructions to boot the rootfs.
I still have a lot to learn about customization and boot sequence. It's my wish to set the options by extlinux.conf.
Hi, could you help me plz and tell me how did u get the interactive shell? I try to get it but dont understand.. I have a serial console and see the kernel debug buuting data, but dont know to enter into shell (I mean booting shell in order to change env’s for booting)
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#20
Fine, I'll try to give an explanation. But I didn't understand which is the shell that you are referring to.

So if you want to access the u-boot interactive shell, you need to connect the USB adapter to an UART, which may differ from a distro to another. E.G linaro is set on UART3 and armbian on UART2 as mainlined default on u-boot. I didn't tried for Android nor Elar Systems nor Debian.

After having found the right UART, you'll need to plug adapter to set the connection and start the communication program prior to boot the Tinker Board. That's in order to catch with the very early option given by u-boot, on the first few seconds.
You may enter on the u-boot shell by pressing any key during the first seconds, which will stop the booting procedure. You might see a writing which is mention it.
So when you stopped, you probably need the correct information in order to issue the right commands, which may give you a particular detail or to try a different booting option. There's a help online which may give some guide.

If you want/need to change the UART, you might read the entire discussion here. But for Armbian, it could be rather different and it will need to write on the /boot/Armbian_env.txt, IIRC.

If you want to enter the kernel shell, it's only needed to wait when it has stopped to show all the messages. In certain cases it might stop prior completion, because it has encountered some error.

Anyway when it stops successfully it will prompt you for an user login, else it might be giving you options to use shell commands or none, according what failure it has encountered.
Light blue words might be a link. Have you try to click on them? Big Grin
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