Yep. Same here. Loaded BIOS 1.2.0 which released today [4th September] and it fixed my issue. When I plug my XPS 13 (9300) into my LG 4k monitor (27UD59) via a Choetech USB-C to DP cable the external monitor works. Before it just didn't. Have tried unplugging and hot plugging usbc cable several times and the monitor is recognised every time and running at 60hz refresh rate. Cold boots also work perfectly. As they should have done all along.
Well Dell you got there eventually so thank you for that. Maybe next time be more honest and open about things. But thanks again and thanks to everyone on here as well, particularly those who helped get us site info about what was going on.
1.2.0 seems to be working now.
The Thunderbolt controller showed v80.00 both before *and* after the update, so that's weird.
@BlipBloop Thunderbolt controller firmware updates are issued as separate packages. They are not part of BIOS updates. (EDIT: Well at any rate, that's how it's been with previous Dell systems. I'm not sure about the XPS 13 9300 since I don't see any TB3 controller firmware updates listed on support.dell.com. I suppose one possible explanation is that it hasn't received an update yet. Or maybe Dell started packaging them into BIOS updates now? But TB3 firmware updates are definitely separate on older systems, such as past XPS 13 and 15 models, and the Latitude 7480 I'm using right now.)
Still seeing the same issue on bios 1.2.0.
My usbc-HDMI has been working ok if connected directly to the thunderbolt port. The issue I have is with the Caldigit ts3 plus thunderbolt dock.
I have two monitors, the one connected to the dock via DP works perfectly. The one connected to the dock via USB-C-HDMI occasionally works, but the resolution can't be set correctly.
I have contacted the support and they said the engineering team aware of the issue and plan to address it on another bios release in November 2020.
I'm going to return my 9300 as my 30-day window ends soon. I was expected this should've been fully fixed on bios 1.2.0 but it doesn't, who knows what might happen in November...
Lucky you, having still window to return. I'd do the same 😞
I'm having similar issues as you have with the docking station (+ one monitor through miniDP works only once every 3,4,5 or more reconnect of whole docking station).
I was thinking about purchasing caldigit tb3 dock too, (I would be closing to spend on docks, hubs, adapters and whatnot, close to what I paid for laptop itself (that's sick :/)). Glad I read your message.
Yeah I guess I am the lucky one here, still too bad I am a big fan of the XPS series and I really like the design of this laptop, My other XPS 13 9370 works perfectly with the same setup.
I got the developer edition and have Arch Linux setup, customized and everything.
For anyone that's interested, the dmesg when I connect the monitor via Caldigit TS3 plus via hdmi/usb-c is:
i915 0000:00:02.0: [drm] *ERROR* Link Training Unsuccessful
Fix it for me, and while I am grateful for the fix I can't say I am happy with the overall experience with the support team and returns of dell, I am staying away from the company from now on.
@marrk42 I realize you mentioned that the TS3+ works as expected with another XPS 13 model, but just in case it's a weird interoperability issue between the TS3+ and the XPS 13 9300, have you updated the firmware of the TS3+? This article mentions some fixes related to USB-C displays connected to the downstream port. Not sure USB-C adapters would qualify, but it may be worth looking into. However, it appears they only provide a firmware updater application for macOS. Any chance you have at least temporary access to a Mac with a Thunderbolt port?
@jphughan nice find, I don't have a Mac at the moment. Will definitely ask around today or maybe run a macOS VM via KVM and try to pass-thru the docking station to the guest...
I can't believe I am doing this lol