Kubuntu 17.04, Dell 7480 and Dell D6000 universial dock, disconnecting randomly.

[Toto]

Hello !
I also have a D6000 dock and it seems to happen less frequently when I plug it with USB3 cable. The dmesg log suggest that it may be a power management issue. Indeed, it seems that the kernel tries to suspend all the devices plugged in the dock. I haven't found a solution yet, unfortunately.

[FrodeJemtland]

Tried to upgrade to the last BIOS for my machine. Dell 7x80 v 1.5.8.

The kernel has also been upgraded to 4.10.0-33-generic

Still have the same issue. Not that hard to reproduce. Just watch a Youtube clip. I'm feeling lucky if I can watch it to the end.

In addition the last couple of days I have also experienced that the external monitors some times is not detected. It might be if they are not connected at a reboot. That is a new effect that is not wanted

[blaise64]

I have the exact same problem with the same dock and a similar laptop (latitude 7280).
I tried several power management config but it failed and i have tried all the proposed solutions in your post (upgrade etc...) without success.

I have a windows dual boot that works fine with same monitor and same dock, cable etc... so i know it is not a hardware failure (except maybe a firmware problem).

The big problem with plugging/unplugging is that some random time it will not reset properly and my windows are split between two screen and all become freezed...

The os is a Linux Mint (Ubuntu 16.04 LTS based).

Does anyone have a working D6000 on linux or another usb-c dock that work under Ubuntu like OS ? If I can't make this dock work i will be happy enougth to bougth another dock if i allow me to not besome insane...

[FrodeJemtland]

I have for this setup a 240W power adapter. I have thought that bigger is better, but it might actually be one of the reasons the problem is so severe.

I noticed that the problem is triggered, when the CPU starts to work. As I wrote in a earlier post, the problem is connected to doing something graphic intensive, like watching a video.

I was questioning someone from work what kind of power supply we usually deliver whit the D6000 dock, and that is 130W. Just for the test of it I replaced the 240W with a 130W, and that resulted in a big improvement. I still have the problem, but maybe only 1 out of 10 times, compared to before the switch....

That was strange.... Doing some more tests.

---- Edit after a week.
This did NOT fix the problem....

[Jérémie]

I have exactly the same problem on my dell latitude 7480. Nobody found a solution ?

[pbeutier]

I can confirm the 1.4 release dont fix this bug...

[FrodeJemtland]

Testet upgradeing Kubuntu to 17.10 hoping this might have a positive effect, to no avail.

Testet another pc, with Kubuntu 17.10 on the same dock and monitors. There everything seemed to work OK.

Not sure what is the big difference, but looking into the graphic card, and drivers/kernel modules.

[FrodeJemtland]

Hi

After I upgraded to 17.10, my mouse is a bit sluggish, so I have searched around for a solution to this. I found a reddit post:

--
Pxxrpsy
There is a reported problem with the kernel 4.13 and some Intel graphics. My computer was crashing constantly and I was blaming Plasma, but it was the parameter intel_iommu that has been enabled by default in 4.13. Try to set the kernel parameter intel_iommu=off and hopefully it will help.
--

This was verry interesting regarding my problem with the external monitors that is being disabled.

I now have kernel version 4.13, so I turned intel_iommu to off, two days ago. I have manged to force the problem only one time after this. The problem do not appear while I sit at the computer, anymore. I have noticed that the external monitores is turned off, a couple of times, if I have left the machine for a couple of hours.

I do still have a sluggish mouse, and the CPU is going through the roof when the screensaver has been running for a couple of minutes... But I think this is related to the upgrade from 17.04 to 17.10.

I'm immensely interested if anyone else with this problem do see effect by changing this option.

To change it if you are on ubuntu/debian, edit your /etc/default/grub, and add intel_iommu=off to the GRUB_CMDLINE_LINUX_DEFAULT line. Then update grub by running update-grub2.
Reboot.

If you try this, please report back if this has helped you, and if the problem has been just reduced, or completely fixed....


-- Edited 2. nov., after a week, with this fix.

This is strange. Once again I see improvement right after the change has been done, but after a day or two the error is back. And I'm back to square one.....