XPS 13 7390 2-in-1 Display and Touchscreen issues

Was contacted by Dell Care, who asked me for the Service Tag and to do a diagnostic test.

Diagnostic Test result was "All tests passed.", however, the problems persist: Either the touchscreen does not work, or the screen flickers / changes brightness rapidly and the Diagnostic LED blink 2 amber and 8 white on reboot. 

Dell Care replied that 2 amber and 8 white is related to an LCD power failure and added, "If you are facing this is out of the box, we recommend you take it back to the store from where it was purchased. However, from our end we can help you troubleshoot further to help resolve the issue." 

I have had Apple Macbooks for 15 years and this is my first Dell notebook, since it had such good reviews. However, I am thoroughly disappointed by the whole experience.

Hi Nemo Cephalopod, we regret that your experience with this new system purchase has not been as expected. We have shared couple of troubleshooting steps via private message to try. Request you to try them and share the results so that we can advice further. ^AM

1. The display flickers and changes brightness, when I turn it on. The diagnostic light blinks 2 amber, 8 white and the Caps Lock light is permanently on. 

Got to intel graphics command center and turn off adaptive brightness under power.

Nope that wasn’t it. 

After hours of performing different diagnostic tests and reinstalling drivers etc, none of which helped, I switched off the notebook for several hours and when I switched it back on, the problems magically disappeared. 

Hope the problem does not magically reappear. 

My new XPS 7390 2-in-1 is also having annoying intermittent issues with the touchscreen and fingerprint reader not working .  The display does not flicker, but the touchscreen stops working if I allow the machine to Sleep whether on battery or plugged in. The fingerprint reader also stops working frequently unless coming off a hard reboot, when is usually works.  I have basically stopped using the fingerprint reader.

Have run the diagnostic tool BIST for the LCD as described here https://www.dell.com/support/article/en-us/sln131497/how-to-run-the-lcd-built-in-self-test-on-a-dell-laptop?lang=en.  Did not get any errors. 

Support Assistant scans come up with nothing.  BIOS is up-to-date as are drivers according to Support Asst and Windows.  Darned annoying.  This is my first Dell in a long time and after all the stellar reviews for this laptop,  I was expecting a better experience with this.

The keyboard also has developed some issues with a couple of keys not depressing/traveling as far as the rest.  Makes typing annoying and often inaccurate.  Was sure hoping this Dell was higher quality.  The price sure was.

If there is a fix for any of this I'd love to know.  Thanks. 

I have the same problem with the xps13 2in1 that i just received.  after waking from sleep, touchscreen and fingerprint reader don't work until i reboot.  Please fix this!!!

Reinstall the system, if it is not possible to go to the repair shop to detect where the problem is, convenient and faster handling

I'm having the same issues as OP Nemo Cephalopod and Domino72 (minus the keyboard being wacky). I've tried a number of power-management and BIOS tweaks described on the Dell and Microsoft Answers forums, but no success so far.

When I boot or wake my 7390, the touchscreen and fingerprint reader are completely unresponsive. (But pen input works.) When I reboot, both the touchscreen and fingerprint reader are re-enabled. (But the fingerprint reader is so inaccurate, I usually have to resort to typing my PIN — despite having trained the fingerprint reader countless times.)

Have any of you tried downgrading the firmware to a previous version? My 7390 is on 1.4.0.

My last two "laptops" were Microsoft Surface Pros. The  experiences (more than just the touchscreen and fingerprint reader) I've had with my 7390 and its flaky Dell Thunderbolt dock have convinced me to go back to a Microsoft Surface Pro if/when Microsoft releases a product with TB.

Plus, all the Dell bloatware that comes with the 7390 (even though I bought it through the business channel)... uggghh. 

Soon after typing my previous post above, I decided to disable all HID device power management. This panoptic approach seems to have solved the issue of the touchscreen and fingerprint reader being unresponsive post-boot. Now, my touchscreen and fingerprint reader work immediately after booting, rebooting, or waking.

Here's the solution that worked for me:

1. Depending on which build of Windows 10 you're running, you may have to set (or even create) the following registry key to 0 (DWORD) in order to see the Power Management tabs in Device Manager:
   
   Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\
   CsEnabled = 0 (DWORD)
   
   
2. Open Device Manager and expand «Human Interface Devices».
   
   
3. Starting with «Converted Portable Device...», open each device in turn and select the «Power Management» tab, if the tab is available. (Not all devices will have the Power Management tab. Also, a quick way to go through all the devices is to select the first one, hit Enter to open the device, hit Esc to close the device, and hit Down-Arrow to move to the next device.)
   
   
4. Uncheck «Allow the computer to turn off...».
   
   
5. Repeat for all HID devices.
   
   
6. Reboot.
   
   

I'm sure I could have been more selective of which devices I unchecked... but I'm going to be lazy and let someone else determine exactly which devices should have Power Management disabled.

Turning off Connected Sleep (the registry edit in Step 1 above) also fixed another issue I was having — the laptop taking 35 seconds to wake up from sleep... and sometimes never waking from sleep.

But, it introduced a new problem — the display not waking properly. The Dell logo would appear for a second, then turn into a square block of noisy pixels, and sometimes the whole screen would turn into noise.

I fixed the display problem by going into BIOS:POST Behavior and turning off Early Logo Display and Early Keyboard Light.

I also turned off Fast Startup in Control Panel:Power Options. I've found that Fast Startup actually results in much *slower* shutdown and startup on modern Windows machines with SSDs.

Now, my laptop wakes up in 1 second (literally) from sleep, goes to sleep in a few seconds, shuts down in about 12 seconds, and boots in 18 seconds. In other words, it's now sleeping/waking/powering like I would expect it to.

As I mentioned earlier, I'm on BIOS 1.4.0., and I'm on Windows 10 Build 1909.

I'm going to hold back on updating to Build 2004 for as long as possible, since that enforces Connected Sleep, regardless of the registry setting.

I have the same problem. My Dell is 3 weeks old. I'm returning it. All the reviewers lied. This computer is the worst I've ever used. Nothing works most of the time. I'm going back to Apple.

I did not use my xps 7390 2 in 1 for a month after turning it on after and installing update the touchscreen stops working... any body have same experience???