Dell XPS 13 9350 + Linux + Thunderbolt 3/USB-C

Ah, that irrational hope that the TB15 will work correctly one day.

Keep it up! :)

The DA200 was working much better under 4.6 or 4.7 but I don't know what comes and goes in the kernel to make things work better or worse. I think 4.8 is worse for i915 drivers, hot plugging and external displays in general.

I created a USB3.0 thumb drive W10 install so I could install patches and such as my original machine was a W10 system until I completely wiped it to install fedora. That may be easier than fiddling with partitions. I don't think upgrading the firmware will solve your issues because the software side is still maturing.

In 4.8, hotplugging seems to be partly working with DA200 USB not working on a hotplug but ethernet seems Ok. HDMI picks up the monitor but no signal goes out.

With 4.8RC5, DA200 and TB15 do not work for me or crashes my system when interacting with external displays. I did order the Intel WiFi as the broadcom prevents suspend from working correctly (so I unload it before suspending) and seems to be weak on signal strength. I'm still having some i915 related crashes once in awhile and screen flickering on the laptop display occasionally. I'm hoping Intel does some more updates on i915 before 4.8 GA and it looks like no more kernel updates related to the dock prior to 4.8GA.

I need to solve these display, adapter and dock problems in the next few months or I need to change out my laptop. Everything works fine under W10 from my perspective.

I also created a Windows usb flash drive and updated the firmware with it. Still DA200 HDMI won't work. So I guess is just as you say, something missing on the software side, not the firmware one.

If you wait "a few months" Dell won't accept a refund for your laptop. I called them exactly for this, and told me (given the Spanish laws) I could have done so in the first 15 days after the purchase or so (I found out the HDMI was fishy way after 15 days - 80 days more or less).

Since I paid through PayPal I started a dispute to talk with Dell about this issue (by phone they would just not think about the problem or try to help -- they just kept repeating that they could do nothing to fix it, and that I couldn't go anywhere or talk to anybody from Dell to fix the issue). They didn't reply yet on the PayPal dispute.

However, and despite my guts tell me that I should return the laptop I have to say that it's a great one, and I think I'll keep it (it mostly depends on how the PayPal dispute goes -- if they are complete ***holes I will return it), and let's see if the software fixes those problems in a short period of time (let's see if we can also help on the linux kernel bugzilla).

Regards.

I've got things working almost perfectly.

I'm using the Intel 7265 card (removed Dells/Broadcom piece of ***). However, my router automatically shifts between 20MHz and 40MHz modes when on the 2.4GHz network. It's the switches that caused the flicker, so I forced my router to only work on 20MHz channel when using the 2.4GHz network in my house. This was the solution.

Not sure why Dell ships hardware with known defects. A little irresponsible if you ask me, but I digress.

I did have to update to kernel 4.8rc6 to get 4k support on my external though. It might've been accidentally removed from 4.7 and earlier 4.8rc versions.

Good luck!

Of course in my last statement I meant the Intel video driver and the Broadcom  wireless kernel driver.

I've had good luck with the new intel wireless card and 4.8rc6 on the xps 13 9350. TB15 USB, ethernet and 2 video outs work (HDMI and mDP). There is sensitivity to dock plug-in sequence. Audio does not seem to work through the dock although the device appears to be detected. I've not checked network performance. I have power management on with the i915 module. I do not have 4K monitors.

I encounter the dreaded CPU pipe X FIFO underrun error occasionally, usually when moving the mouse rapidly between screens) and then there is screen blank on the screen that generates it (I assume associated with the CPU pipe associated with that display) but I'm not getting any other random screen blank/flicker behavior I had before. I do get an occasional flicker on the laptop screen and they are often accompanied by a userif-0: sent link up event (and "link down"). Rapid movement of the mouse between screens does generate some screen flicker.

I am getting NOHZ: local_softirq_pending 08 messages in my journalctl -k -f log watching but that does not seem to cause usage problems.

Suspend while attached to the dock does not seem to work consistently.

I've not tried my DA200 yet but I'll do that next week when I travel.

I upgraded to Kernel 4.8 hoping something would change, but my DA200 simply doesn't work. When using HDMI it still recognizes the second screen but no signal is sent. VGA won't work at all (not even recognize the second screen). Anybody from Dell that may have suggestions? Pro support has proven to be useless in this situation.

I determined the issue not to be with the kernel, but with the 2.4GHz wifi channel. Two things helped me:

First, I found the problem linked to automatically switching 20/40MHz wireless channels when on 2.4GHz networks. I disabled the automatic switching which stabilized the wireless card.

Second, I set my laptop to connect only to my 5GHz network eliminating the hunt for channels altogether. This seems to be 99% stable for me.

It seems that the proximity or lack of shielding between the wireless card and the display hardware causes the issue, be it flickering of external monitors, or non-working externals altogether.

The fact that this problem doesn't exist in Windows means that it's definitely a software issue, but I also blame Dell for not testing this properly before shipping the product.

Just to add my two cents, the problems mentioned here do in fact occur within Windows with both USB-C and Thunderbolt 3 devices, and I wrote about them on my employers blog (we make USB-C and Thunderbolt 3 devices).

The Dell forum is not letting me include a link to the post (I think I'm too new), but if you Google "INVESTIGATING USB-C PROBLEMS ON SOME DELL XPS AND PRECISION LAPTOPS' you should find the page on our website. While I believe it to be obvious, in the interest of full disclosure I work for Plugable Technologies.

I wanted to chime in and add that while I have the same problem with the external display popping in and out, I can mitigate it to some extent by tilting the laptop lid down to 85 degrees or so. It's less than ideal, but it stabilizes the connection and everything appears to work just fine.

If I tilt the laptop lid open past 90 degrees, the connection to the external display gets squirrely again.

I still haven't been able to solve or work around this (which means that I have a useless DA200 sitting in my desk). I think that the time is well beyond when Dell should have said something about this. @Dell: any suggestions/solutions? 

To follow up with my post, I replaced the Broadcom wireless chip with the Intel 7265NGW chip and I've not had any problems with the display flickering since.

I had to make the adjustments on my router.