Upstream kernel and Ubuntu

Hello,

I successfully installed upstream kernel 4.6 on the TK1. Needed to flash upstream u-boot as well and reduced to minimum /boot/extlinux/extlinux.conf bootargs to :

root=/dev/mmcblk0p1 rw rootwait tegraboot=sdmmc gpt

I got fully functional command line, but the GUI is gone.

Would appreciate any hints where the rootfs entry point is and what went wrong.

Thanks

The nVidia driver requires the X11 ABI from the L4T release. The newer kernel is likely working with a different X11 ABI. In that case you would either have to downgrade the X11 ABI to use the nVidia driver, or else go to the nouveau software-rendering driver. This latter case implies loss of hardware acceleration for both video and CUDA (the GPU direct access will be gone).

Dear linuxdev,
Any pointers how to “downgrade the X11 ABI to use the nVidia driver”?

Thanks

That’s a rather big topic. There are a lot of files tied in to X, and the Linux kernel itself may provide its support based on your newer ABI. Even if the kernel does not need ABI changes, as soon as you downgrade the Xorg server you will suddenly find a chain of other things also needing downgrade…the task is far from trivial.

If I were to do this I would start with the current Xorg source and try to build it to match what you have directly on the Jetson. Then I would see if I could use that same environment to build the older Xorg source…very likely you will see a list of missing functions due to libraries being the wrong version. This would then mean getting that older library software and building that…putting in the prerequisite library version one at a time. Each library may also have its own prerequisites and imply the need to downgrade something else. If you get to the point where glibc itself needs downgrade, then you need to build a “glue” wrapper to act as a proxy between newer glibc and the library interface required by the older software.

If you get all of that done, then anything calling a kernel system call will need the same thing…if the kernel only supports a newer interface, then you may have to make changes in either the kernel or the Xorg server.

There is a saying…“if it were easy, someone would have done it by now”. Someone who is an expert in the Xorg software could likely do the job, but for most people this wouldn’t be practical.

Many thanks

Based on that I’d rather stick with L4T kernel, however it is based on 3.10, which is pretty old.
Does anybody know if L4T based on 4.x is scheduled any time soon?

Hi there
I’m trying to boot mainline on Jetson TK1, and I had to upgrade u-boot as well.
Can I ask you some details on how you did upgrade it?

I used this
https://github.com/NVIDIA/tegra-uboot-flasher-scripts/blob/master/README-developer.txt
and have successfully flashed a new version of u-boot. So far so good. BUT, if you go ahead and read the last lines of this
ftp://download.nvidia.com/tegra-public-appnotes/flashing-tools.html
it seems (and I see symptoms of this) that using uboot-flasher-scripts messes with eMMC partition table, and nvflash tool is not able anymore to recognize partitions where to write stuff to.
This means I cannot write eMMC partitions using that tool, and I’m stuck with their old content.

The above link ends with this sentence:
" If you intend to use or repurpose your device for use with upstream U-Boot and Linux kernel, you may ignore nvflash, create a flashable image using cbootimage, write that image to the eMMC’s boot sector(s), and then place a standard partition table at the beginning of the eMMC’s general region. "
That’s me, but I have no idea on how to use cbootimage to create a “flashable image” which comprises all eMMC partitions I need to boot the board

Thanks
j

I just used this:

And it works. I so also other posts doing more or less the same:
https://blog.ramses-pyramidenbau.de/?p=342#bootloader

That’s what I did, and I’ve been able to upgrade u-boot.
Now I would love to upload new kernel images with nvflash, but the
tegra-uboot-flasher utility probably deletes the partition tables at the beginning of the eMMC, which nvflash requires (see last line of ftp://download.nvidia.com/tegra-public-appnotes/flashing-tools.html)

Now, I can use tegra-uboot-flasher to update u-boot, but I cannot upload anything with nvflash, so I’m wondering how to use those two tools together without one compromising the other, or if I can use only tegra-uboot-flasher to update other partitions, including the one where kernel and dtbs are…

I first used standard L4T flash.sh (it wraps nvflash); Compiled the mainline kernel with cross compile. Replaced zImage and .dtb files on /boot. Modified /boot/extlinux/extlinux.conf - with right .dtb file name.

Updated the u-boot to mainline and flash it with those tegra scripts.
The main point is that kernel update is just replacement of files at /boot
This sequence works for me.
Hope it helps

That should work yes, problem is that once you use tegra-uboot-flasher scritp, you cannot use nvflash anymore (at least, I can’t).

I’m keeping zImage and dtbs in a separate partition, but that does not change the main point here: tegra-uboot-flasher makes nvflash unable to read partition table, so a complete re-flash of the eMMC (the --create option, I guess) is required, and this is quite bad if you need to replace kernel image often.
At least, this is my understanding of the issue…