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flickering screen of NC

I played with my NC nearly one week and I like it. But I want to know dose anyone notice the screen of NC is flickering. If you couldn't understand what I mean, please refer to below video,
http://www.youtube.com/watch?v=iDnBSWF44rM
it is not so obvious in real world as in video, but it is noticeable and uncomfortable. I have ipad with IPS LCD but never find this kind of issue. It like some kind of low fresh rate issue in early PC screen, so I want to know whether it is possible to fix it via adjust screen refresh rate in OS level.
Your comments are welcome!

Mine does that but only on the gray background, otherwise I don't see any flickering.

I exchanged my first NC because of this issue. The salespeople thought I was nuts until I demonstrated it for them. My new one still does it but MUCH more faintly and not all the time. I do believe that Barnes & Noble is aware of it (or at least that's something I read in another thread here somewhere..).
It seems to only happen at middling levels of brightness. My first NC exhibited the issue under very specific settings and times, the brightness had to be set between 20%-40% and I had to be displaying a solid area of mid-range colors. I saw it all the time when the screen would dim to display a menu.
From personal experience, you MIGHT be able to get a unit that's better if you exchange. It does seem to be a very common issue, though. Rumor has it that it might be fixable through a firmware update.. we shall see.

I had a pocket pc with this problem many moons ago...The fix was to adjust a trim pot on the display...
No idea if anything like that would apply here, but just wanted to mention it.

I do have similar problem, could any people advise on how to check the refresh rate and increase it?
Many thanks.

Are you planning on rooting or installing another ROM on your Nook? The overclock kernels fix this issue.

from what I see there in the video, if that is what you are seeing...not refresh rate. Rather it looks like a cycling in the backligt control. Almost looks like the PWM duty cycle is out of wack...would explain why it happens at mid range of the brightness.

My first nook color had this problem, I solved it by leaving the brightness up all the time which seemed to prevent it. I got it replaced for other display issues, and my new one doesn't flicker at any brightness, so yeah it sounds like a defect.

Not a defect. It's a problem with stupid coding in the backlight driver.
They set the PWM (pulse width modulation) rate too low, at 40Hz if I remember right. It's easy to fix by setting it up to 60Hz in the driver, which I did in my old Quickie kernel. Totally gets rid of the flicker, and I've seen no side-effects, nor have any been reported to me.
I don't have the time to keep up with the kernel anymore, and for some reason no other kernel dev has pulled my driver fix into theirs. You might talk to Dalingrin or one of the other devs if you really want it, and put them in contact with me at [email protected] and I can help them get it integrated into their kernel.

Can you link to the github commit?
Tx
Sent from my HTC Vision using XDA App

Hmmmm.... my Nook definitely had the flicker issue on most gray colors, especially at dimmer brightness settings. I'm not using your kernel, but I am using Dalingrin's. I haven't seen flicker in months. Could this issue be limited to the stock ROM only?

911jason said:
Hmmmm.... my Nook definitely had the flicker issue on most gray colors, especially at dimmer brightness settings. I'm not using your kernel, but I am using Dalingrin's. I haven't seen flicker in months. Could this issue be limited to the stock ROM only?
Click to expand...
Click to collapse
It appears that way from my experience. I was running the dual boot package with stock and CM7 nightly.
The stock rom flickered very noticeably on greyish type backgrounds. Using CM7 and now Phiremod, the flickering has totally gone away.

Actually the fix is already in init.encore.rc:
Code:
write /sys/devices/omapdss/display0/timings 68000,1024/70/200/40,600/10/11/10
That said, it's going into the driver too.

[Q] blue artefacts / subpixels all over the screen

Hey!
I bought my galaxy 6 months ago. Not long after I noticed a minor issue with my AMOLED display. I could see blue "artefacts" in some bright areas of the screen from time to time. Nothing serious, just blue dots and stripes, subpixels. I even posted a picture of it on reddit (second attachment) more out of curiosity than anything but was later convinced it was probably a software issue. I did have some suspicions something might be wrong with my phone but it actually happened so rarely and the issue was so minor that I just got used to it because it didn't bother me that much.
I recently flashed dark core 2.2 along with rc6 and it got *significantly* worse. I could see blue subpixels all over the screen wherever there's bright white, generally on the lowest brightness setting. Now, I believed that the hardware got worse and it's time to ask for a replacement. So before doing so I obviously had to flash stock firmware and guess what - it all disappeared. So I flashed just the dark core again to go back to rc6 - and it was back again.
The thing is, I really love this ROM and I love the voodoo improvements that come with it. I don't think I can live without them any more. On the other hand, it might be difficult to convince people from samsung that there's actually something wrong with my phone - since it happens so rarely on stock ROM. And I think that this display defect is intensified by the screen improvements from voodoo/dark core.
My only idea is to somehow make it show up on stock ROM and send it to them just then. But is this even possible without rooting my phone? Does anyone has an idea why would these blue subpixels show up in white areas? Is it something they check with specialized equipment or do they boot the phone first to see what's wrong?
Anyway, guys if you could point me in the right direction or had any better ideas... Seriously, It would be helpful even if you said that I should just return my phone and hope for the best. I'm a student and I can't really afford to be charged for returning - what they think is - an operational phone
I attached two pictures
1. a picture of how my screen behaves after flashing the latest dark kernel
2. a picture of how my screen sometimes behave on stock kernels
I'd appreciate any help or advice

Sick of samsung's bad displays

So my display after being replaced 2 times in 6 months started flickering. My phone is very hard to be turned on because of the green flickering.
I just want to upgrade to a S6,S7 Edge or non edge. i just want to know if they have the save problem with displays ? I want to have a phone at least 2 years, can you recommand me a phone like that ?
I was just considering switching to a iPhone even though i prefer android on phones ... o how are S6,S7s displays ? Samsung still have the same problems?

Samsung improved a lot on screen quality in S6 and after, so you should be okay

Dieexe said:
Samsung improved a lot on screen quality in S6 and after, so you should be okay
Click to expand...
Click to collapse
So no more sudden flickering problem ? I mean i didnt even dropped the phone or something like that.

RootNightmareX said:
So my display after being replaced 2 times in 6 months started flickering. My phone is very hard to be turned on because of the green flickering.
I just want to upgrade to a S6,S7 Edge or non edge. i just want to know if they have the save problem with displays ? I want to have a phone at least 2 years, can you recommand me a phone like that ?
I was just considering switching to a iPhone even though i prefer android on phones ... o how are S6,S7s displays ? Samsung still have the same problems?
Click to expand...
Click to collapse
green flickering problem just for auto brightness problem (some custom Roms have this issues) if u will untick the auto brightness u will not have this problem

Not really, it has more issues on this "display green flickering " , on my S5 i dont get display on if the temperature around it getting cold .
Sent from my Samsung Galaxy S5 using XDA Labs

atakan1986 said:
Not really, it has more issues on this "display green flickering " , on my S5 i dont get display on if the temperature around it getting cold .
Sent from my Samsung Galaxy S5 using XDA Labs
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Click to collapse
Wow that's amazing. Been using samsung s5 exynos version for the last 1yr. Never had that kind of problem till date. And it have the same display as snapdragon version. And on comparison I found that this is by far the best display out there when compared to other brands.
Maybe perhaps you might be having a faulty unit from the begining.
Sent from my SM-G900H using Tapatalk

I have the same problem here with the display and it's not a software problem (same by original os 6 and same by cyanogenmod 14).
After the temperatures are under 10 C. i can't open my s5 with home button i must do it over the power button.

Using S5 for more than 28 months still I have not faced any issue. I just had to buy new charger apart from that not a single problem and yes I mess up with my phone so much but I still working and no display failure yet. And also I have dropped it many times, it still refuses to die.
You are just having a defective model or some internals of the phone are messed up. Because Samsh*t produces one of the best displays..

shurupi said:
I have the same problem here with the display and it's not a software problem (same by original os 6 and same by cyanogenmod 14).
After the temperatures are under 10 C. i can't open my s5 with home button i must do it over the power button.
Click to expand...
Click to collapse
So when its over 10C its ok ? Then i should sell the phone when its summer )

nikhil007.n2 said:
Using S5 for more than 28 months still I have not faced any issue. I just had to buy new charger apart from that not a single problem and yes I mess up with my phone so much but I still working and no display failure yet. And also I have dropped it many times, it still refuses to die.
You are just having a defective model or some internals of the phone are messed up. Because Samsh*t produces one of the best displays..
Click to expand...
Click to collapse
At least for s5, the internet is full of this faulty displays, even my friends have same problem.

RootNightmareX said:
So when its over 10C its ok ? Then i should sell the phone when its summer )
Click to expand...
Click to collapse
Very simple but good idea my friend : )
Sent from my Samsung Galaxy S5 using XDA Labs

RootNightmareX said:
At least for s5, the internet is full of this faulty displays, even my friends have same problem.
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Click to collapse
This may be problem for Snapdragon variant then.

nikhil007.n2 said:
This may be problem for Snapdragon variant then.
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Click to collapse
Maybe thats a point, but shouldnt only the processor be different? I assume the display is.the same for both...

nikhil007.n2 said:
This may be problem for Snapdragon variant then.
Click to expand...
Click to collapse
Nope, Exynos variant have this same problem

Im also facing green flickering and blinking at low brightness.
Sent from mySM-G900F using Tapatalk

baseer_IF said:
Im also facing green flickering and blinking at low brightness.
Sent from mySM-G900F using Tapatalk
Click to expand...
Click to collapse
Its not a good sign. Try disabling your light sensor. Even then if you experience such a problem than it means that your flex cable that attaches the screen with the motherboard needs to be changed.
Sent from my SM-G900H using Tapatalk

redhotiron2004 said:
Its not a good sign. Try disabling your light sensor. Even then if you experience such a problem than it means that your flex cable that attaches the screen with the motherboard needs to be changed.
Sent from my SM-G900H using Tapatalk
Click to expand...
Click to collapse
I try to disable Auto brightness. but in manual the problem is persist when when brightness is full low .
if brightness is normal it is normal
Sent from my SM-N9300 using Tapatalk

RootNightmareX said:
At least for s5, the internet is full of this faulty displays, even my friends have same problem.
Click to expand...
Click to collapse
Hi,
Yes and expect the same problems with the following generations. It's an amoled screen thing. The green colour happen when there's a colour displayed on the screen for a very long time (for example, I have a green on my screen of the size of my keyboard).
I think a solution to this problem is to set the display to turn off after 30s (it saves battery too) and maybe, if you're using a custom keyboard, change the colour from time to time. Use the brightness of the screen to a lowest which would still be comfortable to you (and auto unticked).
This last tip alone is enough to prevent greening. My flickering happened after an incredible fall (it had a tempered glass so the screen was safe). The flickering showed green what it had in memory.
Samsung has a 2-year guarantee for its products so you shouldn't worry for that period of time. Problem not solved, replacement.
Best of luck

Superlion721 said:
Hi,
Yes and expect the same problems with the following generations. It's an amoled screen thing. The green colour happen when there's a colour displayed on the screen for a very long time (for example, I have a green on my screen of the size of my keyboard).
I think a solution to this problem is to set the display to turn off after 30s (it saves battery too) and maybe, if you're using a custom keyboard, change the colour from time to time. Use the brightness of the screen to a lowest which would still be comfortable to you (and auto unticked).
This last tip alone is enough to prevent greening. My flickering happened after an incredible fall (it had a tempered glass so the screen was safe). The flickering showed green what it had in memory.
Samsung has a 2-year guarantee for its products so you shouldn't worry for that period of time. Problem not solved, replacement.
Best of luck
Click to expand...
Click to collapse
The funny thing is i already did "by mistake" all the tips you said and still have this. Never dropped the phone though. This problems seems very big though, i expected a burn in to be the biggest problem, but to have flickering at a level that i cant turn on the phone. I wanted recently to switch to a Nexus 6p, but knowing that it uses Amoled too, its a bad ideea. So the only "solution" is to switch to IPS screens? (btw i want a phone that holds on for at least 3 years)

In my research thus far, the AMOLED screen technology is to blame. When the display circuits get old or damaged, they don't sustain current at low power settings. In LED screens, a back light controls brightness, but AMOLED screens send current to each pixel for brightness control. If the circuit is damaged, or any corrosion has built up inside, this could attenuate the current below the point required to sustain light flow. I see this problem with some LED and CFL lights on motion sensor switches. Just enough current goes through the motion sensor to keep it's circuits active, and that current causes a flicker in the light.
With the screen though, since the problem is only resolved when you increase the brightness just a bit above minimum, it seems anything that lowers the display power (auto brightness for example) will cause it to flicker if this setting gets too low. I also noticed that before the screen locks on timer, it dims to low power for a few seconds and flickers as a result. There are apps that attempt to resolve this by putting a translucent black screen over your desktop and apps. This keeps the power up on the pixels but adds a black overlay, kind of like a screen filter. You can adjust the darkness if you need it to save your eyes when reading in the dark but it doesn't help save power any. They also require a rooted device, which could void warranties. The reason for this I believe is because apps are supposed to operate in a way they don't intrude on each other, and a filter that lays over your screen does in fact alter the output of your display rendering. With the added security concerns of these apps possibly collecting screen shots and sending them to another site, I would avoid this. Best to use a physical screen overlay you can put on or remove as needed as long as it doesn't interfere with your touch screen options.
Ultimately, these devices were meant for replacement every 2 to 3 years so if you're like me and you like to make your investment last, best thing to do is apply any work around you can come up with. A repair shop may be able to wipe the circuit boards down with a solution that clears away corrosion, but it won't repair any weakened pixels. I'm still using a Samsung S5 G900F
- And i finally got this fixed. it sounds like the reason for this is that since the latest update your phone cannot decide whether to use hardware or software back light settings. I managed to make the problem go away by doing this:
Go to settings >> system >> About device.
Find "Build number" and click 6 times fast on it.
You will then get the message saying: "You are now a developer"
and then go back to Settings >> system >> Now you will see the "Developer Options"
Now go to Developer options >> Drawing Section or Rendering Section >> Find "Turn off hardware overlays" or "disable hardware overlays" >> This will force the phone to always use GPU for screen adjustments. no more flickering.
but If I turn the brightness ALL the way down, it still flickers like crazy, however, if that's the only time it'll do it, I consider that a win.
Read More :good:

Low Brightness Flicker (LineageOS & Stock too?)

Hi, sorry if this was posted before, but with XDA moving to XenForo, search seems messed up, i did several searches and nothing comes up for "flicker" in this whole Pixel 4 XL Forum...
Has anyone else dealt with the low brightness screen flicker? I know it can't be just a bad phone, since i just bought three pixel 4 XL phones and they all exhibit this same behavior.
They are all running LineageOS (Official builds) so I don't know if this just affects the ROM or stock as well (although I've read it might affect stock phones too elsewhere).
It makes the phone pretty difficult to use in very low light situations, the screen will constantly flicker (more noticeable on darker backgrounds).
At first I thought it was just the Opera browser (as that's what I prefer), but it's operating system wide... Apps like "Darker" help.... because you can crank up the phone brightness and use a filter to dim the screen.... but it doesn't get the top & bottom menu/buttons, so those remain like spotlights in your eyes with that workaround.
Just curious if anyone knows whats up with this... it's the only phone I've ever seen this behavior on (and i've used Pixel 1,2,3 XL phones all with Lineage, and a myriad of other devices back in the Cyanogenmod days.... I've never seen a screen flicker issue like this).
Thanks for any help
edit / update-
the pro version of "darker" app works to fix this.... you crank the phones brightness to 100% and with the pro version you can dim the rest of the interface.
hopefully this helps anyone else suffering from this HUGE flaw (again i don't know if its just LineageOS or not, i didn't run stock on these except to unlock bootloader etc)

Hi,
I've seen it once and solved it by switching off smooth display. Not a real solution of course, but I never really noticed the difference between 90Hz and 60Hz anyway.

edwinek said:
Hi,
I've seen it once and solved it by switching off smooth display. Not a real solution of course, but I never really noticed the difference between 90Hz and 60Hz anyway.
Click to expand...
Click to collapse
hmm.... you running stock i guess? i don't see smooth display option in lineage

Question Problem with purple-pink hue on the main Camera - S21 Ultra Exynos

Hi,
I've noticed pink spot/hue issue in the middle of photos taken by main camera my S21 Ultra (Exynos version).
I've checked that some condition must be met to recreate the problem:
- photo must be taken indoor when sunrise appear (but it should be dimm in the room not bright)
- photo taken outside when is cloudy (there is no sun)
- the light must be natural
- on gray and green (khaki) surfaces defect is more visible
Do you also have this problem?
I was send phone to service center twice:
first time camera module was replaced - unfortunately the defect remained
second time - the service stated that the phone and camera is functional
P. S. - laser AF is not a cause - I've covered up and hue still exists.
I've searched forums and found similar problem with xperia z3, htc, galaxy s5 .
I dont know if this is normal, or maybe software update will fix the problem or maybe this is hardware failure?
Really...don't know what to do anymore.

Have you tried to replicate the results using another camera app? If it looks the same, then it's not software.

77cats said:
Have you tried to replicate the results using another camera app? If it looks the same, then it's not software.
Click to expand...
Click to collapse
Yes - hue was visible in other applications as well as in the service menu.

nevellan said:
Yes - hue was visible in other applications as well as in the service menu.
Click to expand...
Click to collapse
Definitely a hardware issue buddy... Keep trying with Samsung, print the images you showed us here and give them with the phone so they can see directly and not test it barely and not notice...

@nevellan
Good to see that you created this thread.
I've been noticing the same too from the beginning. Enquiring further, I noticed the same in two other units later. (All Exynos).
I did not /do not see the pink hue when the laser AF is covered.
However, my concern is why to have the pink hue in certain lighting condition irrespective of laser AF is covered or not! This is an issue.

... have also noticed that the pink hue disappears when focus enhancer is ON.

Pink Hue dissapers when focus enhancer is ON,becuase then is used wide camera not main (108 MP).

Virgo_Guy said:
... have also noticed that the pink hue disappears when focus enhancer is ON.
Click to expand...
Click to collapse
Try to hide the laser lens..if you still have this , it's a faulty main lens .

UNIK97122 said:
Try to hide the laser lens..if you still have this , it's a faulty main lens .
Click to expand...
Click to collapse
Not sure*.
Could be firmware.
Try:
Clearing the system cache
Clear cam data
Hard reboot.
Check cam settings; excessive contrast or saturation could cause it.
A factory reset will do nothing more than likely.
*test to see if it's purple fringing with some high contrast images ie backlit subjects
Chromatic Aberration: What It Is and How You Can Avoid It
Discover everything you need to know about chromatic aberration, including what it is and how to avoid it for beautiful results.
digital-photography-school.com

blackhawk said:
Not sure*.
Could be firmware.
Try:
Clearing the system cache
Clear cam data
Hard reboot.
Check cam settings; excessive contrast or saturation could cause it.
A factory reset will do nothing more than likely.
*test to see if it's purple fringing with some high contrast images ie backlit subjects
Chromatic Aberration: What It Is and How You Can Avoid It
Discover everything you need to know about chromatic aberration, including what it is and how to avoid it for beautiful results.
digital-photography-school.com
Click to expand...
Click to collapse
I did everything you suggested many times - it didn't help.
Covering laserfocus doesn't help either.

nevellan said:
I did everything you suggested many times - it didn't help.
Covering laserfocus doesn't help either.
Click to expand...
Click to collapse
If you can return/exchange it do so.
No need to suffer from the get go.

Had this issue with my Galaxy S6 long ago as well. I guess it's normal?

trenzterra said:
Had this issue with my Galaxy S6 long ago as well. I guess it's normal?
Click to expand...
Click to collapse
not at all...

I'm having a similar problem with a purple patch in the middle of the shot but only when photographing black objects in less than ideal light conditions, particularly black materials. The problem exists with the main camera and wide angle, Zooms seem ok. The problem also exists using GCAM. If I force flash there is no problem. Doesn't seem to be an issue in any other circumstances. Strange. S21 U Exynos 16gb.

I ve noticed this too, but only on the gray colors. I am up to date with the software version, july patch. Exynos 256 GB.

StefanMagu said:
I ve noticed this too, but only on the gray colors. I am up to date with the software version, july patch. Exynos 256 GB.
Click to expand...
Click to collapse
Plus, i haven t notice this thing until seeing this thread and tried to photo something gray, so i think this is not a big deal.

StefanMagu said:
Plus, i haven t notice this thing until seeing this thread and tried to photo something gray, so i think this is not a big deal.
Click to expand...
Click to collapse
Ignorance is bliss

Looks like only Exynos devices are plagued with this defect, one more reason to pass on this problematic SoC.

https://www.reddit.com/r/S21Ultra/comments/n13697