GPD User Community Support Forum

Backlight flickering

I have a similar situation but no flicker. Same circumstances but my screen simply will not resume. I have to press power button (screen stays off) and I hear the Ubuntu MATE dialog which asks what I want to do. I press enter and it shutsdown. Then I fire back up.
Happens intermittently. Since using New Ubuntu MATE p2 max ISO I have yet to see it happen but its very early days.

I’m assuming your both on Bios 0.24 as I am?

yes, bios 0.24 and debian buster with 5.2 kernel from buster-backports.

v0.24 as well (with Arch linux)

Ok, very interesting. I am getting a slight flicker in the same situation but hear me out please as this is very odd.

Firstly, my setup:

  1. P2 Max 0.24 Bios
  2. Ubuntu MATE 19.10 (p2 max specific ISO released 17th October 2019)
  3. I have for some time suffered with intermittent screen going blank.

Today this happened (I had USB C hub connected and HDMI out to a LG Wide monitor):

I was working on p2 max in emacs making changes to a LaTeX file when I had to take care of some other work on my mac so I spun my chair around and sent a few emails from the other device. I came back to my P2 Max to find it had turned off the displays (power saving mode) but not standby or hibernated.

I move the mouse, and only the external monitor displayed (I am extended not mirroring) Weirdly I can move the mouse off the screen but cannot see anything at all on the p2 max screen only on my external monitor connected by HDMI. I was just about to reboot the device (as I;ve had to do a lot) when I get called away back to the mac.

I spent maybe 20 minutes reading and looking at some websites on the mac and P2 Max had turned external display off again (power saving) this time though when I moved the mouse. The p2 max screen and my external screen came back BUT I have a slight backlight flicker on the p2 max screen.

(One reason I may not have noticed this before is because I have the brightness at 5% most of the time)

Very odd.

Interesting! Did the flicker fade after some time?

More details about my experience. When the flicker started, I rebooted into windows and observed that the problem persisted. I shutdown windows and kept the machine off for maybe 2-3 minutes. Then rebooted into linux (another kernel version), the flicker was still occurring. Then left the machine on, then noticed the problem seemed to be less and less visible, over a period of about 2-3 hours until it was barely noticeable. Then shutdown and packed the machine. When turning it back on, no more flicker.

The fact that it persisted across reboots/shutdown should give hints to someone who knows how the firmware+hardware deals with the screen+backlight power. Is GPD open enough to provide schematics or additional details to help us figure this out?

It would be very interesting to get a similar report from a windows user… or alternatively, for a few weeks to pass without any windows user reporting such a problem, which given the number of windows users, would lead us to believe that the linux vs windows difference in handling screen power off is the place to check.

At this point, we have reports from 3 different users running 3 different distros (though probably very similar kernel versions). The ubuntu mate p2max may also become popular and we’ll have more reports, “hopefully”.

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Ok it seems like that I also run into the issue, but mine was triggered while I tried to hackintosh. Somehow after finishing the screen started flickering and after rebooting to Linux / Windows the problem persisted.

Then I just left it on the table and went out for a walk. When I came back the flickering has already gone.

@PeterCxy which bios version were you running when problem occurred?

0.27, but frankly I think this should be some sort of hardware issue that got triggered accidentally by some part of my hackintosh process, cuz otherwise it shouldn’t just go away when I left it alone for some time…

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II’m still on 0.24 bios simply because Kendyz advises that 0.25 was not public yet?
Clearly it was included in the firmware pack.

Not sure how @PeterCxy has 0.27 can only assume he is working closely with gpd team.

Also I have no idea what the differences are with 0.24 / 0.25 / 0.26 or 0.27.

My issue of flicker still occurs intermittently as @joshwiththegoodhair mentions when the screen enters sleep (not suspend or hibernate) and then is resumed. But I’m more concerned with my screen not resuming from sleep than the slight flicker as if I wait long enough or power down for an hour or two the flicker is gone.

I’m on gpd p2 max specific Ubuntu mate 19.10 iso.
For the record I only have Ubuntu Mate and no other windows or hackintosh partition.

Yesterday, the screen didn’t turn back on after screensaver. I let the machine powered on and did nothing, then when moving the mouse 2-3 hours later, the screen came back to life, without flicker. I’m still on 0.24 + debian buster.

I don’t know, I just went to their website and saw there was something newer than 0.24, I remember it’s 0.27 somehow…

The specific GPD message regarding the 0.27 firmware is “This is the 0.27 version BIOS of P2 Max that solves the problems of scratch screen,two different screens,half screen,some vertical lines on the screen,if you don’t have these issues,please don’t upgrade it.” I’m unsure of this does anything for flicking screens?

I’m not 100% positive, but I think that in addition to this issue happening after a suspend -> resume, I also think this might be related to either a USB-C hub (with PD/power delivery) OR using a power adapter that’s over 12V (like 15V or 20V). Can anyone (@admin) who has had this issue verify this is (or isn’t) the case for them, and I’ll research further.

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Happened to me today. Windows 10 Pro x64 1909 with December update. The system was closed and powered on and plugged in to a 5v 2.4A USB adapter. Picked it up and opened the screen and the flickering looks almost like a slow screen refresh rate to me then a backlight as I only see it on colors and not white.

BIOS 0.24 and occurs in BIOS/UEFI firmware settings as well.

I was using the GPD provided USB source when it happened. The p2max has been running pretty much 24/7 and I didn’t update the bios, yet it didn’t happen again. I don’t have more clues.

But I thought more about it and wondered whether I originally correctly identified the symptoms. I said it was the backlight, but it may be the lcd itself flickering, because indeed, it was more visible on colors/darker zones than on white/bright zones.

Well, I shutdown yesterday and powered back on and it still appears to be happening. How long did it take to stop for you and did you leave it on or off?

A few hours later it was invisible, the machine was kept on but the display was off (screensaving).

@joshwiththegoodhair (I’ve only ever used the USBC cable and the Genuine adapter that shipped with the GPD from memory I cannot remember what that was but the max Volts/Amperage was posted on this forum.)

Mine still intermittently flickers from time to time usually if left to idle to screensaver for extended period and then I resume from. My Bios is still 0.24. Recently I noticed that even if I shut it down and left it powered off for 5 minutes on starting up it was still flickering eventually it either stops or my eyes adjust to it and I don’t notice it as much.

Drastically reduced by this evening but still slightly there. Hopefully it is something GPD can fix through either a display specific driver or firmware but at least it feels usable again, at first it was so bad I couldn’t stand to look at it

I just had the same issue.
Laptop was open and running for ah hour or so with micro-hdmi to HDMI screen projection using just the external screen, laptop was plugged into a equivalently rated power supply via USB-C.

Then I locked the laptop when I walked away for a few minutes and upon returning after waking the laptop it was using the laptop screen and the backlight was flickering.
Turning down the backlight to it’s lowest setting confirms it’s the backlight and not the graphics driver.
In the past I’ve had other laptops have the same problem caused by it rapidly swapping screen refresh rates, but the p2max only has a 60htz refresh rate in Windows 10.