Where did mkknlimg go?

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

Hi All,

I'm using a raspberry pi 2B with a custom kernel compiled from sys-kernel/raspberrypi-sources. So far i've been using sys-kernel/raspberrypi-sources-4.19.9999, and now i'm updating to 5.4.9999.
With kernel 4.19 i had to compile the kernel and run scripts/mkknlimg to create an image which i could use under /boot. With kernel 5.4 mkknlimg is gone, what is the correct way of working with 5.4?

Thanks in advance.
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USE="-war" emerge --newuse @world

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NeddySeagoon · Posted: Sat Jan 11, 2020 10:45 am Post subject:

pa4wdh,

mkknlimg has not been required for a long time.

You install the kernel modules the normal way.
The *.dtb go into /boot (I think mkknlimg combines them)

On ARM (32 bit) I think bzImage works for your kernel, if not, its Image.
Depending on how you load the kernel, you may need to rename it. What to depends on how you load the kernel,

You can use any name you like if you have kernel= line in config.txt
If you use bootcode.bin autodetect, it needs to be kernel7.img

Don't forget to update your firmware before you install the kernel bits and pieces.
The firmware update will provide everything your kernel build does and more. You do the firmware update first, so your own build overwrites the provided firmware when there is a name collision.
You can prevent the name collision if you want to.

Did you know that later Pi2s have 64 bit CPUs?
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

NeddySeagoon · Posted: Sat Jan 11, 2020 11:36 am Post subject:

pa4wdh,

Read the text along the GPIO pins. If if says "Raspberry Pi 2 Model B V1.1", Its a BCM2836 which was an expensive Pi2 only CPU. Its 32 bit only.
Later Pi 2s are fitted with the 64 bit BCM2837. With very good eyesight you can read the numbers on the top of the CPU, unless you have a heatsink on it :)

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

Thanks for all the info Neddy.

The text(s) on the hardware are very hard to read, it's all covered by a HAT (a GPS HAT, i use it as a NTP server).
The firmware seems useful

The firmware i'm using now is dated 23rd of july 2017 when got them from github. So i'll give that (and kernel8.img) a try.
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

NeddySeagoon · Posted: Sat Jan 11, 2020 1:51 pm Post subject:

pa4wdh,

I use the kernel and firmware from the Foundation git tree.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

Some things worked, some things didn't.

I installed the raspberrypi-firmware package, and after the obvious file collisions have been resolved and I placed back my original cmdline.txt and config.txt my 4.19 kernel booted without a problem. Also when i replaced it with a zImage of the 4.19 kernel (so without using mkknlimg) it worked.
When i copied a zImage of my 5.4 kernel and all dtb(o)'s to the correct places it didn't boot at all, so for now i'm back to 4.19.
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

NeddySeagoon · Posted: Sat Jan 11, 2020 4:31 pm Post subject:

pa4wdh,

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

Thanks for your help Neddy. I was trying to find my way info troubleshooting and come to similar questions.

NeddySeagoon · Posted: Sun Jan 12, 2020 12:14 pm Post subject:

pa4wdh,

That the rainbow never goes away shows that one of the files need to boot is not found.
As swapping kernels make it work, its down to the kernel and its matching .dtb.

You mostly get away with not updating the .dtb but every now and again ...

Check for mismatching kernel and *dtb filenames in /boot and config.txt.

You get a console right away as you have CONFIG_FB_BCM2708=y and its a module by default.
I use the default config with a few tweaks, so its a module here.

You have all the CPU frequency governors built

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

NeddySeagoon · Posted: Sun Jan 12, 2020 1:23 pm Post subject:

pa4wdh,

I have kernels on Pi3 and Pi4 in 64 bit mode. I also have the cross compile toolchains for the Pi1 and Pi2 up to date.
My Pi1 is running my GPS clock. Its an early one, with only 256M RAM. As you say, at 600MHz its seriously overpowered. :)

I've dug out a Pi2 and I'll try to reproduce your kernel here. It won't be for 5 hours or so until I start.
Its sunny, I'm told I need to tidy up the garden right now. :)
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

Thanks for you help Neddy.
Take your time, there's no need to hurry. i understand that sometimes there are other thinks more important than gentoo

_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

NeddySeagoon · Posted: Sun Jan 12, 2020 6:56 pm Post subject:

pa4wdh,

Your kernel starts for me. Here's what I did.
Updated my git repos for the kernel and firmware.

Put your .config at the top of the kernel tree

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

Thanks for the test Neddy, good to see the kernel boots on your Pi.

There are two differences in what we're doing:
1) I'm compiling native on the Pi with gcc 9.2.0, you seem to cross-compile, which version are you using?
2) You stick with the default filename (kernel7.img), just to be 100% sure i did the same and it did not make any difference.

It would be nice if you could share the compiled kernel with me to see how it works on my Pi.
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

NeddySeagoon · Posted: Sun Jan 12, 2020 10:17 pm Post subject:

pa4wdh,

My Pi2 boot is online.
I built the kernel and dtb files with the gcc-9.2 cross compiler.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

Thanks for providing all the files.

I've tried a few different steps:
First i thought i'd do a quick fix and just loaded your kernel7.img to my Pi and rebooted. This gave the same result as my own binary.
Then i downloaded your complete /boot and placed it on my sdcard and booted the Pi ... still the same result.
Now the only difference was my cmdline.txt and config.txt so i moved them out ... still the same result.

Is there a way to get more information from the Pi so see why it doesn't boot?
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

NeddySeagoon · Posted: Mon Jan 13, 2020 10:20 am Post subject:

pa4wdh,

If its really not loading the kernel, you can get very little.
If you have a 3.3v USB to serial cable, then the serial port on the Pi is available but that will only show messages after the kernel has started.

The way the green LED flickers provides some diagnostic information. It all varies from model to model though.
Its on the Foundation website.

Can you try another SD card, or remaking the /boot filesystem on the one you have?
Only /boot matters until you get to Waiting for rootfs ...
The rainbow is gone by then, so that's enough to test that the /boot filesystem in OK.

I think that there is a debug option for config.txt but I've never used it.
I don't know where the debug info is emitted.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

I actually cleaned and re-created /boot after i experimented with your /boot files.

I cleaned /boot, re-emerged rastberrypi-firmware, copied the dtb(o)'s, copied config.txt, cmdline.txt and of course the kernels. Still, same result. The only think i can do to have a more from-scratch start is to actually format the partition and start over.

On a failed boot this is what the LED's do:
1) First, the red led lights
2) The green led gives a few (very) short blinks, i guess this is from accessing the sdcard for it's files in /boot.
3) Then there is one distinctive longer blink of the green led, this might be an indication for the problem
4) Both leds turn off and the system becomes unresponsive to anything but a power-cycle.

All documentation i found describe multiple flashes of the lights and the sequence repeats, both don't seem to happen in my case.
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

NeddySeagoon · Posted: Mon Jan 13, 2020 12:27 pm Post subject:

pa4wdh,

The on a Pi2, the Red LED is power good. Its lit when the supply voltage is above about 4.6v.
Try a different PSU.

This page is worth a read. In particular,

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

It would indeed be strange for a newer kernel to cause such a change in the power requirements, but to be sure i did some tests.

I have tried 3 "power supplies":
1) A dual charger 5V/2A which i normally use to power the Pi
2) My regular phone charger 5V/1A
3) A USB 3 port on my laptop which should be capable to providing enough power for the Pi

I have tried 2 cables:
1) The cable i usually use to power the Pi (which advertises itself as a high-quality power-only cable)
2) The USB cable i usually use to power/connect my phone

All combinations gave the same result: Kernel 4.19 boots perfectly, kernel 5.4 doesn't.

Then i removed the ethernet cable (lower power consumption), removed the GPS hat and connected a multimeter to the 5V and GND pins on the GPIO connector. The USB port on my laptop provided the best results, keeping it around 5V regardless of the load. The power supplies both dropped to about 4.85V, even when ethernet and the GPS hat are connected and all 4 cores are fully loaded.

Long story short, i don't think this is a power supply problem.

I also tested the scenario where i configured a kernel in config.txt which does not exist. In that case i saw the green led blinking (forgot the number of times it blinked) and the pattern repeated.
_________________
The gentoo way of bringing peace to the world:
USE="-war" emerge --newuse @world

My shared code repository: https://code.pa4wdh.nl.eu.org
Music, Free as in Freedom: https://www.jamendo.com

NeddySeagoon · Posted: Tue Jan 14, 2020 10:32 am Post subject:

pa4wdh,

OK, we have learned lots of things that it isn't. That's a start.
Don't be too taken in by multimeter readings. That tells the average voltage, so its useful but not conclusive.
5v with 1.0v of ripple (4.5v to 5.5v) is worse than 4.8v with 0.2v ripple (4.7v to 4.9v).
Its good to know that when the Red LED goes off, its not the power failed. The Pi has shut down.

That you get repeated attempts to boot when the kernel is not found is good. That's the repeating flashing Green LED.
It indicates SD card reads.

Lets rule out a corrupt kernel file.

On the SD card I booted from, I get

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

NeddySeagoon · Posted: Tue Jan 14, 2020 2:54 pm Post subject:

pa4wdh,

I'm sort of running out of ideas.
Post

pa4wdh · l33t Joined: 16 Dec 2005 Posts: 910

It's sort-of nice to see i'm not the only one puzzled by this ...

The outputs you requested: