Steam Deck screen flickering at 40 Hz (probably PWM).

[Adravil]

Hello there!

I asked the Support yesterday about this problem, but was, excuse me my straightforwardness, dumped here without any answers. So here I am.

Steam Deck's screen is heavily flickering at a 40 Hz frequency point and that flickering is still noticeable in the range, approximately, from 30 Hz to 50 Hz. From my tiny experience such behavior may be, only may be, a symptom of the PWM-controlled backlight brightness of the screen. I definitely have an old revision Deck, at the very least because of the Delta fan, and that's why asked the Support (presuming the problem is indeed PWM-related, so softwareably-incurrable) if this problem was mitigated in the newer Deck revisions. But, again, received no answers. I am adding links to video recordings (shot by myself) on YouTube to show you approximately what it looks like. Videos were recorded at 1080p 240 fps, and saved at 30 fps; I have also put the web-synchronized clock in the frame, so you can see what's the real frequency of oscillation (240/30=8, every second during recording is being stretched to 8 seconds on the record).

The reason for creating this topic is (again, presuming the problem is indeed hardware-related) I want to know if such a problem had already been cured in the newer Deck revisions. And if not -- will it be in future ones and when. If it's somehow still software-related -- when it will be cured (currently sitting on the latest stable Steam OS version).

https://youtu.be/EoCWbVXSD2c
https://youtu.be/LwUCXvObEJw

P.S. Answering beforehand to folks who don't suffer from this problem -- I am happy for you and sincerely wish you all only a pleasant experience from using this device. I also sincerely like this device and use it daily, its purchase resurrected a rare feeling of holding a completely new and interesting piece of technology in my hands. But I am literally painfully locked out from using Deck with a refresh rate set in between 30-50 Hz, I can't look at the stroboscope without receiving a headache and eye pain.

Edit 1: removing the "backlight" word from the header and the body of the post after shadowboy813 brought an idea of the problem potentially being caused not by the inaccurately controlled backlight brightness, but by the too-slow refresh rate of the screen itself. Thank you shadowboy813!

Edit 2: also adding new videos, mentioned in the topic, here, at the top:
https://youtu.be/jYQCdcEoaTU
https://youtu.be/llYIOQHB-mQ
https://youtu.be/NAWYFrGGLcg
https://youtu.be/E6NttyQaVco

Update as of 2023-06-15:

* Thread on Reddit:
https://www.reddit.com/r/SteamDeck/comments/145whl4/steam_deck_flickering_at_40_hz_any_new_ideas_on/

* Support (quite expectedly) didn't confirm nor deny utilizing the LCD Backlight Strobing feature in the Deck's screen. Since symptoms are similar to what the RTINGS team wrote here
https://www.rtings.com/monitor/tests/motion/black-frame-insertion
, I created a topic with the request to help investigate the problem with the screen
https://www.rtings.com/discussions/rIygqzomjCwbQCMx/steam-deck-s-screen-flickering-at-40-hz-pwm-lcd-backlight-strobing-something-else

* For those who suffer from the same problem, the best I can recommend is to bring up the refresh rate to 48-50 Hz or lower the brightness to 30-50%. It feels like also colors, shifted to the warmer side (display "night mode"), are having some impact too, but that impact is quite minor (both warmer colors and the brightness decrease only mask the problem, but brightness change is more effective).

* There's also a 1200p Deck screen custom project growing up now
https://www.deckhd.com/
, but, of course, who knows what it brings. 720p on 1200p may look blurry, it may have the same flickering problem since being limited to the same 60 Hz refresh rate, the replacement will surely not be easy, and all of that. But will see. At least some diversity may appear in the result.

[Prezidentas]

Does the PWM frequency change with the display refresh rate?

[vanishedchief2021]

I've tried 40hz on my deck and with the naked eye it's not that bad what settings on the camera did you use.

[vanishedchief2021]

If you are sensitive to this remember always use in a well lit room. Some people are even sensitive to 60 hertz.

[Punkovich]

I understand that certain people claim to be more sensitive to framerate/refresh times, what I don't understand what issue the video is supposed to demonstrate: If you film at high rate and slow it down you can see the screen refreshing?

[Adravil]

Originally posted by Škoda 14Tr:

Does the PWM frequency change with the display refresh rate?

I have no instruments to measure the PWM oscillation frequency, unfortunately. So I can't tell you for sure. Purely subjectively visually -- probably yes. Theoretically -- I think also yes, it fits my testing results:

* setting the screen refresh rate at 40 Hz makes the problem most prominent;
* while after setting it at 35 or 45 Hz the problem becomes not so noticeable;
* and after setting it at 30 or 50 Hz the problem looks like being unnoticeable anymore; gone or not, but not noticeable.

But again, I can't measure, and I'm not a proper engineer.

[Adravil]

Originally posted by vanishedchief2021:

I've tried 40hz on my deck and with the naked eye it's not that bad what settings on the camera did you use.

Thank you for the test, and I am glad that you don't face the same problems! What about the camera settings -- unfortunately my OnePlus 9R doesn't provide me with a lot of settings for the Slow-Motion camera mode of the default camera application (or at least I am too blind to find them). So I won't be able to provide you with such details too, sorry. If you know some good popular-secure free camera app for Android that is able to shoot video at 120+ fps and allows me to review/change its settings for that mode too -- please let me know, I'll install it, make a new record and share it with everyone including you.

[Mahjik]

The challenge here is that different people will be affected by different levels of PWM. I'm not aware of an official measurement that can be listed on devices to know whether a person will or will not be affected. As far as I'm aware, it's a trial and error type thing for those who are sensitive to it (today).

[Adravil]

Originally posted by vanishedchief2021:

If you are sensitive to this remember always use in a well lit room. Some people are even sensitive to 60 hertz.

Thank you for taking care! That indeed makes sense and I'm always trying to remember to use my smartphone, Deck, and similar devices only in well-lit rooms, to keep my eyes healthy as long as possible. I also wish all the people, who suffer from the same problem, to solve it as soon as possible (let it be even worse than mine, at 60 Hz). But that doesn't change anything for me. Neither the same/worse problems of others, because I'm talking about myself now, nor how well-lit the room is, because I still can the flickering even on a bright day.

[Adravil]

Originally posted by Punkovich:

I understand that certain people claim to be more sensitive to framerate/refresh times, what I don't understand what issue the video is supposed to demonstrate: If you film at high rate and slow it down you can see the screen refreshing?

No, the screen refreshing is not the problem, the screen backlight switching between "on" and "off" states, and even more -- doing it improperly (I assume -- too slowly), is the problem.

The short answer is: I have shot it because I know no other ways how, with the help of the camera I possess, I can capture a problem I see with my eyes. If there are some other better ways -- I'm open to suggestions. If from an engineer's perspective it's meaningless -- so be it.

The average answer is: I am not an engineer, so I have shot such a video initiatively, to demonstrate to engineers how my screen (backlight, first of all) works in detail, and let them decide if they see, for example, badly adjusted and so causing problems PWM there, or if not -- maybe some other problems instead.

The long (subjective) answer is: maybe(!), those vertical dimmer lines, moving horizontally, are pixels, which backlight is set to "off" at the moment. And since I see the flickering of the backlight, probably(!) the frequency of switching between "on" and "off" states (oscillation, in short) is too low. In terms of the video, it means that the dimmed lines are moving too slowly. The backlight of my screen is switching between "on" and "off" states too slowly, to slow for my eyes to not notice it.

[Adravil]

Originally posted by Mahjik:

The challenge here is that different people will be affected by different levels of PWM. I'm not aware of an official measurement that can be listed on devices to know whether a person will or will not be affected. As far as I'm aware, it's a trial and error type thing for those who are sensitive to it (today).

I agree with the "different people will be affected by different levels of PWM" part, but not completely. To my (subjective(!)) understanding, I doubt you'll be able to find people who suffer from PWM being set at a higher frequency, and not suffer from it being set at a lower frequency. In other words, PWM configuration is not about "guessing the right value". Instead, you have a mass of people having zero problems with PWM being set at some frequency, and a less number of those, who have problems with the same PWM. If you decrease the frequency, more people will start seeing it. And back, if you increase it, fewer people will complain. In other words, PWM configuration is about "setting high enough value".

But again, my (and, I believe, your) ideas are just ideas. I appreciate your time, but our deep-mind ideas have zero impact right now. Let's see what Deck developers say. It may be not a PWM at all. I have no intention to rush to blame something or someone, knowing nothing about the topic. I just want my Deck screen's backlight to stop flickering at 30-50, and mostly at 40 Hz, that's all I want.

[Mahjik]

Originally posted by Adravil:

Originally posted by Mahjik:

The challenge here is that different people will be affected by different levels of PWM. I'm not aware of an official measurement that can be listed on devices to know whether a person will or will not be affected. As far as I'm aware, it's a trial and error type thing for those who are sensitive to it (today).

I agree with the "different people will be affected by different levels of PWM" part, but not completely. To my (subjective(!)) understanding, I doubt you'll be able to find people who suffer from PWM being set at a higher frequency, and not suffer from it being set at a lower frequency. In other words, PWM configuration is not about "guessing the right value". Instead, you have a mass of people having zero problems with PWM being set at some frequency, and a less number of those, who have problems with the same PWM. If you decrease the frequency, more people will start seeing it. And back, if you increase it, fewer people will complain. In other words, PWM configuration is about "setting high enough value".

We basically said the same thing. At this point in time, there isn't an actual measurement that companies know and can use. Companies aren't purposely creating products to make people feel uneasy or ill but they don't fully understand this effect (nor the actual cause). I personally do not have an idea of what it is or isn't, but it seems something hardware specific that is unlikely to change with a software update.

[Adravil]

Originally posted by Mahjik:

Originally posted by Adravil:

I agree with the "different people will be affected by different levels of PWM" part, but not completely. To my (subjective(!)) understanding, I doubt you'll be able to find people who suffer from PWM being set at a higher frequency, and not suffer from it being set at a lower frequency. In other words, PWM configuration is not about "guessing the right value". Instead, you have a mass of people having zero problems with PWM being set at some frequency, and a less number of those, who have problems with the same PWM. If you decrease the frequency, more people will start seeing it. And back, if you increase it, fewer people will complain. In other words, PWM configuration is about "setting high enough value".

We basically said the same thing. At this point in time, there isn't an actual measurement that companies know and can use. Companies aren't purposely creating products to make people feel uneasy or ill but they don't fully understand this effect (nor the actual cause). I personally do not have an idea of what it is or isn't, but it seems something hardware specific that is unlikely to change with a software update.

Oh, alright, so we agreed here.

No, no blaming. They may have intentionally added the cheap risky screen backlight controlling module, but they still have created a great device in the end. No one is expecting V1 to be perfect, but great it is already.

Yes, I believe that's hardware-specific too. That's why I mentioned revisions at the start of the topic, not just an abstract "fix".

But no matter what -- I am still waiting for Valve's response (let me remind you again that Support provided me with 0 responses).

[germanicianus]

@Adravil, this flickering can also be visually caused/worsen by interference with another flickering light source, e.g. energy saving bulbs - speaking out of experience.

Do the following test:
1) Switch off all artificial light sources including other screens.
2) Switch off the Deck‘s adaptive brightness and set it to full brightness.
https://cdn.windowsreport.com/wp-content/uploads/2022/09/enabling-disabling-adaptive-brightness-steam-deck.jpg
3) Test different screen refresh rates.

[Adravil]

Originally posted by germanicianus:

@Adravil, this flickering can also be visually caused/worsen by interference with another flickering light source, e.g. energy saving bulbs - speaking out of experience.

Do the following test:
1) Switch off all artificial light sources including other screens.
2) Switch off the Deck‘s adaptive brightness and set it to full brightness.
https://cdn.windowsreport.com/wp-content/uploads/2022/09/enabling-disabling-adaptive-brightness-steam-deck.jpg
3) Test different screen refresh rates.

While I should admit that the changes you asked me to make indeed had some positive impact on "reducing" the flickering ("reducing" in any way; at least because of switching off the adaptive brightness), unfortunately, the problem still remains, is clearly noticeable and painful.

40 Hz:
https://youtu.be/jYQCdcEoaTU
https://youtu.be/llYIOQHB-mQ

60 Hz:
https://youtu.be/NAWYFrGGLcg
https://youtu.be/E6NttyQaVco

P.S. My excuses for my shaky hands.

[Punkovich]

I would propose that it's not going away at 60fps, it just happens to be synching better with the camera speed at that rate. Like filming a propeller:

https://youtu.be/jQJckIWIklg