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.

[Adravil]

İlk olarak Punkovich tarafından gönderildi:

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

Probably. I understand what you are talking about and agree that, technically, it's probably not vanishing after switching to 60 Hz. But I personally, with my eyes, don't see it at 60 Hz, and see it at 40 Hz. And my camera captures the same results: static image at 60, and flicking at 40. Videos are not the reason of complain, but the only evidence I have now. Or even just example.


PWM can stay on the Deck as long as needed, no one is asking to remove it right at this moment. As long as it's not painful for me to look at the screen, as long as I don't see the PWM working -- I'm fine with it. If all of this is a PWM at all.

[shadowboy813]

You could always just run the device at full brightness, when the backlight is at 100% duty cycle.

Edit: I just did a 240fps slow mo of mine at at both half and full brightness, and yes, I'm seeing left-to-right flickering even at full brightness--ruling out PWM. At full brightness, PWM would have a 100% duty cycle, so no flickering. This is not a backlight strobing issue (as that would be a global flicker, not a left-to-right flicker, like I see in both yours and my video) but scanline flickering as the SD's display is scanned left to right.

This is why it's worse at 40Hz instead of 60, because the screen is being drawn slower, making the flickering more obvious. If the issue is causing distress and battery life is the reason you're choosing 40Hz, it might be worth the reduced eyestrain by setting it to 60hz and half the frame rate. Sure, you're losing responsiveness by going to 30fps, but the scanning frequency increases from 40hz to 60hz. (This is why 30fps has less flickering than 40fps for you)

I very highly doubt PWM for screen brightness is going to be at such a low frequency, typically it happens at a much higher frequency than the display refresh.

[Adravil]

İlk olarak shadowboy813 tarafından gönderildi:

You could always just run the device at full brightness, when the backlight is at 100% duty cycle.

Edit: I just did a 240fps slow mo of mine at at both half and full brightness, and yes, I'm seeing left-to-right flickering even at full brightness--ruling out PWM. At full brightness, PWM would have a 100% duty cycle, so no flickering. This is not a backlight strobing issue (as that would be a global flicker, not a left-to-right flicker, like I see in both yours and my video) but scanline flickering as the SD's display is scanned left to right.

This is why it's worse at 40Hz instead of 60, because the screen is being drawn slower, making the flickering more obvious. If the issue is causing distress and battery life is the reason you're choosing 40Hz, it might be worth the reduced eyestrain by setting it to 60hz and half the frame rate. Sure, you're losing responsiveness by going to 30fps, but the scanning frequency increases from 40hz to 60hz. (This is why 30fps has less flickering than 40fps for you)

I very highly doubt PWM for screen brightness is going to be at such a low frequency, typically it happens at a much higher frequency than the display refresh.

Finally, some interesting comments with valuable info and suggestions start to appear. Thank you!

* "Run the device at 100% brightness to eliminate problems" -- later on in the text, as I understood, we both agreed that it's not solving anything. All the videos I've shot were shot at 100% brightness. And you confirmed it personally, as I see.

* "That's not a PWM-caused flickering" -- that may be true, I have only suggested it, I'm not an engineer. The real PWM itself indeed shouldn't cause any trouble, at least, when being utilized at 100% brightness.

* "Should be global, not left-to-right" --
** Well, firstly, in all videos depicting (at least trying to depict) a PWM (like here, I've picked one at random: https://www.youtube.com/watch?v=0CIb7gXIPSk ), I've never seen the screen flickering entirely, but instead with running black lines; and to me, personally, it makes sense -- just like the image is being drawn line by line, the backlight brightness is being changed in the same way too; nothing is being done instantaneously, only fast enough for you to not notice;
** Secondly, (it's, probably, not a big deal, but) what you call "left-to-right" is, actually, "top-to-bottom", since Deck's screen is, actually, rotated (see any video showing how Windows is being installed on the Deck);

* The reason I'm attempting to use 40 Hz, is because the Deck is not powerful enough to run all games at 60 Hz + 60 fps even on minimal graphics settings. The shorter battery life isn't a big deal for me. 60 Hz + 30 fps and 50 Hz + 50 fps are working variants too, true. But 30...50 fps, is the gap I can't use: 40 Hz + 40 fps doesn't work properly and there's no 80 Hz + 40 fps option (let me remind you that the game at 40 fps has lower input latency, than at 30 fps). So I either enjoy around 60 fps or tolerate 30 fps, nothing in between is possible for me.

Overall, I agree that it may be not a PWM at all, but simply the "too slow" screen refresh rate (there're no 30 Hz and 80 Hz options to test the theory, but it still is nice, I admit). But I'd still like to hear a word from Valve Support if I can do something to it, if they can do it, if they plan to, anything. My purchased device has a feature I'm unable to use.

[Punkovich]

OK, so we have established:

-That it is not PWM
-That your unit is operating the same way as others
-That the issue described is simply the normal operation of an LCD screen
-That the way it works is not a problem for the vast majority of users

Therefore we must conclude that the fault lies with your special little brain that processes images faster than 99.9% of the population. You're not going to hear from Valve on this issue as by their reckoning there is no issue, everything is working as intended.

I think we have also solved the question of why you were 'dumped' here by Support. Your complaint showed them you lack understanding of the technology and/or are a crazy person and they hoped the forums would have more patience to deal with/educate you.

[Adravil]

İlk olarak Punkovich tarafından gönderildi:

OK, so we have established:

-That it is not PWM
-That your unit is operating the same way as others
-That the issue described is simply the normal operation of an LCD screen
-That the way it works is not a problem for the vast majority of users

Therefore we must conclude that the fault lies with your special little brain that processes images faster than 99.9% of the population. You're not going to hear from Valve on this issue as by their reckoning there is no issue, everything is working as intended.

I think we have also solved the question of why you were 'dumped' here by Support. Your complaint showed them you lack understanding of the technology and/or are a crazy person and they hoped the forums would have more patience to deal with/educate you.

Reported and blocked. Please, save your and our time and stop leaving messages on this topic. Have an easy day and take care.

[shadowboy813]

İlk olarak Adravil tarafından gönderildi:

* "Should be global, not left-to-right" --
** Well, firstly, in all videos depicting (at least trying to depict) a PWM (like here, I've picked one at random: https://www.youtube.com/watch?v=0CIb7gXIPSk ), I've never seen the screen flickering entirely, but instead with running black lines; and to me, personally, it makes sense -- just like the image is being drawn line by line, the backlight brightness is being changed in the same way too; nothing is being done instantaneously, only fast enough for you to not notice;
** Secondly, (it's, probably, not a big deal, but) what you call "left-to-right" is, actually, "top-to-bottom", since Deck's screen is, actually, rotated (see any video showing how Windows is being installed on the Deck);

The steam deck's display is a portrait display rotated. We're saying the same thing. It's presented sideways, so the screen draws sideways. My "left-to-right" is referring to the display as presented to the user. Top is completely arbitrary from a software standpoint.

Secondly, PWM flickering will be global since the backlight applies to the entire screen. The LEDs illuminate the ENTIRE panel from the back, just like a CFL backlit panel does. Only with OLED and CRTs are each pixel individually illuminated (1 line at a time on a CRT, even)

[Adravil]

İlk olarak shadowboy813 tarafından gönderildi:

İlk olarak Adravil tarafından gönderildi:

* "Should be global, not left-to-right" --
** Well, firstly, in all videos depicting (at least trying to depict) a PWM (like here, I've picked one at random: https://www.youtube.com/watch?v=0CIb7gXIPSk ), I've never seen the screen flickering entirely, but instead with running black lines; and to me, personally, it makes sense -- just like the image is being drawn line by line, the backlight brightness is being changed in the same way too; nothing is being done instantaneously, only fast enough for you to not notice;
** Secondly, (it's, probably, not a big deal, but) what you call "left-to-right" is, actually, "top-to-bottom", since Deck's screen is, actually, rotated (see any video showing how Windows is being installed on the Deck);

The steam deck's display is a portrait display rotated. We're saying the same thing. It's presented sideways, so the screen draws sideways. My "left-to-right" is referring to the display as presented to the user. Top is completely arbitrary from a software standpoint.

Secondly, PWM flickering will be global since the backlight applies to the entire screen. The LEDs illuminate the ENTIRE panel from the back, just like a CFL backlit panel does. Only with OLED and CRTs are each pixel individually illuminated (1 line at a time on a CRT, even)

Alright, alright, I just wanted to remind you about that, maybe the direction was important somehow 😄

So we presume that such flickering is not a badly-configured PWM issue, but simply a too-low screen refresh speed.

Here is a separate topic about the screen upgrade for the Deck to support the 80 Hz mode, by the way:
https://steamcommunity.com/app/1675200/discussions/0/3816284554961695644/

While "no matter what we conclude here, it makes sense for me to test other users' Decks personally (and I'll do that as soon as I have a chance)", between, for example, other Deck owners living relatively nearby, I was able to find quite a few people who claim not to see any problem of such kind on their Decks. What do you think, even after we found a good explanation, is there still a chance that my and your Deck's screens are just broken? I'm sure it sounds funny, but I want to have a strong reason to throw a variant away. And "something is broken" is a meaningful answer to many problems 😄

[germanicianus]

@Adravil, a nice informational video about flicker when taking videos:
https://m.youtube.com/watch?v=FLQMvDfERrs

[Adravil]

İlk olarak germanicianus tarafından gönderildi:

@Adravil, a nice informational video about flicker when taking videos:
https://m.youtube.com/watch?v=FLQMvDfERrs

Alright, so how do I drop my eye's shutter speed to 1/40 to stop noticing my Deck's screen flickering at a 40 Hz refresh rate? 😄

[germanicianus]

@Adravil, your LCD screen definitively has a hardware issue. I'm on SteamOS 3.4.8 and just went into the game Portal and lowered my Deck's refresh rate to 40 Hz via the 3-dot-button using the refresh rate slider. The game's vertical sync was on. There was no flickering at all, and no tearing, perfectly smooth, even with adaptive brightness switched on.

Therefore I recommend to utilize your warranty and get a replacement Steam Deck.

[sunspark]

Looks pretty bad in the videos.. I'll have to take a look at mine later and see if my phone is able to see anything though I generally use only 60 because I like smoothness but I can make a suggestion all the same.

Try 45 Hz instead of 40 Hz.

The math in the electronics may work out better since it is a divisor of 60, i.e. 30 is 1/2 60, and 45 is 3/4 of 60.

It's strange how the video looks because on my desktop monitor I use 23.976 Hz all the time to watch videos, but that is v-synced to the video playing so there is no flicker at all.. Drawing the screen of course is separate from backlight flicker which has its own refresh rate and there is no backlight issue on my monitor at the brightness I use.

I wonder if there is a deck issue where the backlight frequency changes a bit when the panel refresh changes or the video chip or something. I agree with the OP that it looks awful and it sure never looks like that on a desktop monitor.

[Adravil]

İlk olarak germanicianus tarafından gönderildi:

@Adravil, your LCD screen definitively has a hardware issue. I'm on SteamOS 3.4.8 and just went into the game Portal and lowered my Deck's refresh rate to 40 Hz via the 3-dot-button using the refresh rate slider. The game's vertical sync was on. There was no flickering at all, and no tearing, perfectly smooth, even with adaptive brightness switched on.

Therefore I recommend to utilize your warranty and get a replacement Steam Deck.

Wow, thank you for your time and a quick test! I'm thinking about a replacement too, but would like to test some other user's Deck personally first.

Actually, I'd be nice if the whole story ended like a simple hardware bug. It would at least mean that Valve won't have to apply a software fix or release a hardware revision. And we wouldn't have to wait (or at least I).

Thanks!

[Adravil]

İlk olarak sunspark tarafından gönderildi:

Looks pretty bad in the videos.. I'll have to take a look at mine later and see if my phone is able to see anything though I generally use only 60 because I like smoothness but I can make a suggestion all the same.

Try 45 Hz instead of 40 Hz.

The math in the electronics may work out better since it is a divisor of 60, i.e. 30 is 1/2 60, and 45 is 3/4 of 60.

It's strange how the video looks because on my desktop monitor I use 23.976 Hz all the time to watch videos, but that is v-synced to the video playing so there is no flicker at all.. Drawing the screen of course is separate from backlight flicker which has its own refresh rate and there is no backlight issue on my monitor at the brightness I use.

I wonder if there is a deck issue where the backlight frequency changes a bit when the panel refresh changes or the video chip or something. I agree with the OP that it looks awful and it sure never looks like that on a desktop monitor.

Hey!

I should say that today this bright idea came to my head too. I switched my PC monitor to somewhere 20 Hz refresh rate and have seen... 0 problems. That of course doesn't instantaneously answer any of my questions, but to say that this moves me one step closer to consider a replacement -- that's for sure.

Thanks!

I'm still looking for a kind Deck user nearby to run a test personally on that device... 😶

[sunspark]

Try 45 on your deck, is it still the same as 40?

[Adravil]

İlk olarak sunspark tarafından gönderildi:

Try 45 on your deck, is it still the same as 40?

Yes, in the range of 40-50 Hz it is still noticeable, the closer to 50 Hz -- the less. At 50 Hz it is, it feels like, no longer noticeable.