Laptop screen goes blank when plugged into power

I’ve been a witness of yet another bizarre thing yesterday. Sister brought her HP X360 with her and when she plugged it into a wall, screen went blank. As soon as I’ve unplugged it, screen came back. WTF!? I could clearly see laptop was still running just fine in the background, it was just the screen going all black.

I’ve predicted it has to do something with the power plan, but I didn’t think it would be what I found out later…

The reason for this is the reversed control for screen brightness!

Setting it to maximum brightness when plugged in like so…

…causes the screen to go blank when plugged into a wall socket because max brightness setting was actually maximum dimming in this case!

After trying the quick keys on keyboard to adjust brightness, same thing was observed, increasing brightness actually decreased the brightness of the screen and decreasing it actually made the screen brighter. I have no idea why this is happening, must be software or firmware bug or some missing special driver from HP that didn’t get installed with clean Windows 10 installation.

How to fix it?

Move the “Plugged in” slider all the way to the left and “On battery” somewhere closer to the right side. That should stop the screen going full black when you plug in the laptop.

So, before you throw your laptop into a bin or send it to service center, try this. It just might be the same (bizarre) issue. 🙂

Display not waking up after being turned off overnight

So, another rant time. My PC is turned on pretty much 24/7, including when I’m sleeping. I set the music to play on low volume, sometimes I run BOINC client or something, so basically system is running. But since I don’t need display, I always turn it off. In the morning, when I wake up, try to turn the display on and then  it’s rage mode on.

Display refuses to wake. Smashing keyboard and mice, nothing. Music is playing normal, Caps and Num lock responds on keyboard and I can also control music with keyboard multimedia controls. Only way to get to the system was to reset it.

So, I checked on The Internet and found out there are LOADS of people with such problems. Mostly seems to be related to Windows 7, Windows 8 in combination with AMD Radeon graphic card (usually HD7xxx series). I didn’t think of it because with Windows 7 I never had such problems, only when I switched to Windows 8.1. I’m using AMD Radeon HD7950 3GB with AMD Catalyst 13.12, so that’s where similarities with other reports started to make sense. Supposedly this problem was happening before, AMD fixed it with some Catalyst version and now with Catalyst 13.12 WHQL, it seems to be back again.

What’s even more annoying is the difficulty of reproducing this issue. It’s not enough to keep PC running and turn off the display by hand, it actually has to be over night. Like AMD drivers are checking that display is turned off over night and it fucks up everything with that. Because when I turn off display through the day, I never had this problem, even though the conditions were identical and the display was turned off for the same period of time (~6 hours). So, 6 hours over day and the problem never happened to me. Have it turned of for 6 hours over night (between midnight and 7 AM), pretty much every single morning, the damn thing won’t wake up when I move the mice around.

I’ve tried everything, changing USB devices sleeping, changed CPU C states, disabled ULPC for graphic card, checked BIOS settings, nothing.

Symptoms:

Display won’t wake up after being turned off over night with PC actually running and not being in a sleep state. Display is set to turn itself of after PC is idle for 15 minutes. Keyboard and mouse seem to be responsive, but Windows refuses to wake up the display. Pressing ON/OFF button on display doesn’t make any difference, changing input mode (between VGA and DVI) using display built-in settings (or button) doesn’t make any difference. It just stays in sleep mode.

This only happens if display is turned off over night for ~6 hours. It never happened when PC was in the same exact conditions over day. Seems like AMD throws the graphic card into some sort of deeper sleep state if it’s night time based on local time read from user computer. And since it’s happening mostly on AMD HD7xxx series which have ZeroCore feature, it seems to me like AMD fucked it up pretty badly.

Temporal solution:

What seems to work for me is to unplug DVI cable from graphic card and plug it back in. This seems to re-initialize the connection and the desktop instantly appears on the screen. Same should apply to HDMI and DisplayPort connections.

Some say switching to lockscreen in Windows 8 also wakes up the display, but I haven’t tested that yet.

Permanent solution:

Well have to wait for AMD to fix this damn thing. Anyone with friends at AMD who could speed things up? Because it’s really annoying and widespread issue with no real solution other than the above.