HP Laptops 'Losing' connection to LG WebOS Tv's over HDMI

[LordX]

So, this is a weird one that I am experiencing on two different laptop/TV setups connected via HDMI.

The TV's in question are LG WebOS 4k TV's but different models/sizes from different years.

Note: I never lose the signal while using the laptop. It is always perfect during use. Both laptops are set to always be on, and never turn off the video output.

It is when I turn off the TV and then come back later and turn it on (or if I have it on another input for a while like a Roku and then switch back). It will show NO INPUT/SIGNAL DETECTED when the laptop is clearly on. Sometimes it works when I switch back, sometimes it shows no signal....

The only way I have found to fix it is to power off the laptop and power it back on. Then it IMMEDIATELY shows video again, even at the BIOS level.

Any ideas on what may be causing this? Some silly setting on either the laptop or TV sets that may be impacting this?

 

[LordX]

Since a restart always works - is there a way to set a key combo (Like CTRL ALT R) to initiate a system restart? That way, I don't need to see any picture in order to 'fix it'.

I did find a little more key combo way: WinKey + X, then press U, then press R

 

[britechguy]

Were I you, I'd just create a desktop shortcut that runs: shutdown /r /t 0
then assign that whatever 3-key shortcut you wish, which could be CTRL + ALT + R

See: https://woshub.com/shutdown-restart-windows-cmd/
Section: Create a restart shortcut on Windows Desktop

You can, of course, change the switches to the shutdown command to make it do exactly what you want it to do in the timeframe you desire. The above is an immediate restart with zero warning.

 

[LordX]

Very nice - will implement this on both systems. This way I can force a reboot either from the keyboard, or through teamviewer if things get wierd.

Also, I was reading through the options - is there a shut down option that you know of that reloads everything that WAS up before the reboot happens? Windows Update restarts that happen overnight will do this, where most of the things that were up before the update happen are back. Would be nice to have this happen with the force restart. I saw the /sg switch, but that says it reloads all 'registered' apps - don't know if this is the same thing I am looking for. Pretty much just want Chrome etc to come back with the tabs that were in use automatically when the system reboots.

 

[britechguy]

I'd play with the /sg switch to see if the result is what you're seeking.

I've never come close to trying out every switch on the shutdown command and tend to learn actual behavior for other options/switches through direct experimentation.

 

[LordX]

Played with it a bit - looks like if you replace the /r switch with /g it reboots and reloads previously open programs (as long as it isn't required to force shut them down apparently)

 

[Markverhyden]

Out of curiosity are those new HDMI cables? Technically there is a difference between DMI cables.

HDMI Cables: Types and Specifications Explained | Eaton

HDMI is the most popular way to transmit digital audio and video to a TV or computer monitor. We answer all your questions about HDMI cables... types, resolutions and features to consider.

tripplite.eaton.com

 

[LordX]

Yes, and interestingly, I DID run into issues years ago during the transition into 4k TVs with my old NUC. I would randomly have the screen black out DURING use - and when I upgraded the old HDMI cabled to 2.0 - problem solved. So yes, all the cables now are HDMI 2.0 or better.

SOLUTION: After doing some thinking - I kept having the feeling that this is an issue with the display driver or something similar. So I googled if there was a keyboard combo that resets the graphics driver. Sure enough, there is! When I used this combo this morning, without having to restart the machine - it worked! It's like it re-initiates the 'handshake' with the TV.

The combo is: Windows key + Ctrl + Shift + B

 

[Blues]

To add to the bit about HDMI specs and issues I found many the better branded cables bought prior to newer specs were made over the original specs and often work at specs above their original released spec. I have spare HDMI cables still only rated as 1.3 or something that work with 4K HDR TVs, devices, and content w/o issue. Basically if you buy cables don't buy the bottom of the barrel, also don't buy Monster brand, I think either LTT or GN (Gamers Nexus) or both have done some testing on cables and specs to show how well or poor different brands perform and within what specs. I think Monster actually was one of the worst performing and definitely at its price point not that I recommend or use them anymore I think when their price point went up too much and too many good budget options came into the market they really just became a bad option.