Hi
We do not want to screen out the log information printed by the system startup during the TX2 module startup. How do we set off the TX2 startup information printing?
The console log output is something most Linux distributions set up within the kernel boot parameters, and Ubuntu is much the same. If you run command βcat /proc/cmdline
β, then you will probably see the tokens βquiet
β and βsplash
β (RedHat/Fedora substitutes βrhgb
β, RedHat Graphical Boot, for βsplash
β, but it is the same thing, different logo). So your goal is to remove βquiet
β and βsplash
β from the command line.
Assuming you are configured for use of β/boot/extlinux/extlinux.conf
β, look for the βAPPEND
β key/value pair. This is one long line starting with βAPPEND
β, and followed by a space delimited set of values. β${cbootargs}
β is content inherited from prior boot stages, while everything past β${cbootargs}
β is new content being added. Find βquiet
β and βsplash
β, and remove those.
Tip if you work with extlinux.conf
for more advanced situations: You can duplicate that block with the LABEL
and create a second block which is duplicated other than any LABEL
. Then, if you have serial console during boot, you can pick an alternate boot entry, e.g., one with an experimental kernel or experimental command line arguments. If you donβt have a serial console, then it would just boot to the DEFAULT
label anyway. You donβt need to do this for splash
or quiet
, but thought Iβd mention it since it might be useful later.
I donβt quite understand the method you mentioned. How to operate on the TX2 platform to mask the system startup printing information?
Maybe I am missing what you really want. It sounded like you were missing boot messages, but wanted those messages. Now it sounds like perhaps you want to avoid seeing messages. Can you clarify?
If you are speaking of messages from when the bootloader has just started running the Linux kernel, then either is easy. However, if we are talking about boot messages prior to Linux running (bootloader or earlier), then things become a bit different (and difficult).
In normal state, when TX2 starts, the screen will output startup information, including kernel startup information. However, we do not want these information to appear on the screen during the startup process. During the startup process of TX2 system, the screen will not display any startup information, but directly enter the system after startup.
This might require more than one step, but if you are only considering the HDMI output, then this may not be too difficult. Serial console output (which exists separate from HDMI) occurs even before Linux, and so if you wish to change serial console in addition to HDMI, then the process is more complicated.
If you want to see the current arguments passed to the kernel at the moment it starts running, see βcat /proc/cmdline
β. Keep in mind that there are two possible ways to pass arguments to the kernel, and depending on how things are set up for you, this could alter instructions slightly.
Take a look at the file β/boot/extlinux/extlinux.conf
β. Within that the βAPPEND
β key/value pair is passed to the kernel as command line arguments. If you compare the output of βcat /proc/cmdline
β to what is actually in the extlinux.conf
APPEND
content, youβll see the argument is larger. The start of that is via the environment variable β${cbootargs}
β, and this is inherited from boot stages prior to the kernel loading. Then the rest of the APPEND
is from extlinux.conf
. Your goal would be to change kernel arguments from extlinux.conf
if possible, but there may be cases where you need some device tree changes (this is where the ${cbootargs}
is initially created prior to Linux loading).
Indirectly you may find it useful to know that for most arguments the last argument is the final argument the kernel uses. For example, if I saw βrootfstype=ext2
β as I read the cmdline
, and then later see βrootfstype=ext4
β, then the actual type is ext4
and it is as if ext2
was never used. Consoles have two types though, serial and the usually physical terminal, and so you might see two console arguments and both would be used (so long as one is serial and the other the local HDMI terminal).
The basic goal for removing HDMI messages is to remove this:
fbcon=map:0 console=tty1
(depending on circumstances you might see only fbcon=map:0
and not console=tty1
β¦any console naming a serial UART can be ignored as this is for serial console)
Also, the βquiet
β parameter hushes some scroll anyway, so you might want to make sure that is present. The βsplash
β argument adds the graphical image during quiet
times.
What is your default output from βcat /proc/cmdline
β? What do you see within extlinux.conf
for the βAPPEND
β key/value pair?
Probably most of what you want can be done via removing the βfbcon=map:0
β from extlinux.conf
, and adding βquiet
β if it is not already present.
Note: APPEND
is a single very long line with spaces delimiting tokens. Be sure to keep this as a single long line.
If you still have the argument present, then you might need to work on the device tree as well. If you need to change serial console output prior to Linux loading, then this too probably requires device tree edits (the part that initially creates β${cbootargs}
β).