VESA Adopts Adaptive-Sync

[Mand]

first a-sync laptop maybe...
http://h10032.www1.hp.com/ctg/Manual/c04188028.pdf

Lots of laptops have eDP as well as panel self-refresh (PSR), for power-saving functions. That doesn't mean they have A-Sync.

My German isn't all that great, otherwise I'd delve into the link provided. This is the first I've seen of a display manufacturer commenting directly on A-Sync or the standards, so I'm very curious to know what they're saying.

 

[Phynaz]

Adaptive sync does not yet exist.

Sure it does.

Displayport Adaptive Vsync is a technical specification. The specification exists.

What you trying to say is there are not any commercially available implementations of the specification available yet.

Considering the specification is a few days old that is to be expected, no?

 

[sontin]

My German isn't all that great, otherwise I'd delve into the link provided. This is the first I've seen of a display manufacturer commenting directly on A-Sync or the standards, so I'm very curious to know what they're saying.

Philipps and AOC said that G-Sync is superior to Adaptive-Sync (=>more features) and it doesn't influence their decision on bringing G-Sync displays to the market.

 

[Mand]

Sure it does.

Displayport Adaptive Vsync is a technical specification. The specification exists.

What you trying to say is there are not any commercially available implementations of the specification available yet.

Considering the specification is a few days old that is to be expected, no?

Given that people have been claiming the CES demo from five months ago proves that it does exist, it's important to be clear. Adaptive Sync has not yet been demonstrated - ever. We don't even know if the VESA spec will work yet. Sure, the spec exists, but just having defined a spec does not mean you'll be able to meet it.

 

[monstercameron]

http://www.vesa.org/wp-content/uploads/2010/12/DisplayPort-DevCon-Presentation-eDP-Dec-2010-v3.pdf [page 24]

Main New Feature for eDP 1.3: Panel Self-refresh
Frame buffer can also be
used for LCD overdrive to
improve 3D performance Description of Panel Self-refresh
•  Frame Buffer in TCON can maintain display image without
receiving video data from GPU.
•  For a still video image, this allows the GPU to enter a low
power state and the eDP main link to turn off.
•  Allowing the GPU to power down between display updates
will save significant power and extend battery life.
•  Except when watching a movie or playing a game, there
are many times when the video does not change for
multiple frames. How Panel Enters Self-refresh Mode
•  GPU determines when display will not be changing
and sends Self-refresh Entry command to display
using SDP (secondary data packet); TCON then
enables frame buffer, captures video frame, and
then GPU and Main Link turn off.
•  Display continues to Self-refresh from TCON frame
buffer, using asynchronous timing for display. How of Panel Exits Self-refresh Mode
•  When GPU detects new image data (for example from a
keystroke or mouse movement), GPU wakes up TCON
eDP input and starts sending the new display image data.
•  Display then switches from the Frame Buffer to eDP input
data, and Genlocks display timing to GPU. Single Frame Update
•  While in Self Refresh Mode, the GPU can make single
frame updates to the TCON frame buffer; the display
maintains asynchronous timing during the process.
•  This can be used to turn on or turn off a blinking display
cursor, for example.
•  A burst of single frame updates can also be used, for
example to fade-in and fade-out the blinking cursor.

 

[MrPickins]

Given that people have been claiming the CES demo from five months ago proves that it does exist, it's important to be clear. Adaptive Sync has not yet been demonstrated - ever. We don't even know if the VESA spec will work yet. Sure, the spec exists, but just having defined a spec does not mean you'll be able to meet it.

On the same line of reasoning, just because it hasn't been demoed in its final form doesn't mean it is impossible to implement.

 

[caswow]

Philipps and AOC said that G-Sync is superior to Adaptive-Sync (=>more features) and it doesn't influence their decision on bringing G-Sync displays to the market.

they just say what nvidia told them. why wouldnt they? they want to sell this so they wont say async is better or whatever.

 

[Mand]

On the same line of reasoning, just because it hasn't been demoed in its final form doesn't mean it is impossible to implement.

That it hasn't been demoed in any form is a reasonable justification for being skeptical, though, yes?

they just say what nvidia told them. why wouldnt they? they want to sell this so they wont say async is better or whatever.

You're going to have to do better than conspiracy theories. Why wouldn't they want to sell A-Sync displays too?

 

[Phynaz]

We don't even know if the VESA spec will work yet. Sure, the spec exists, but just having defined a spec does not mean you'll be able to meet it.

I don't recall VESA ever standardizing a specification that didn't work. I think it's pretty safe to assume that the VESA standards setting task group members know what they are doing. Especially considering that the people creating the spec work for the companies that are ultimately responsible for implementing the spec.

Nvidia even has a seat on the BOD.


http://www.vesa.org/about-vesa/member-companies/

 

[sontin]

http://www.vesa.org/wp-content/uploads/2010/12/DisplayPort-DevCon-Presentation-eDP-Dec-2010-v3.pdf [page 24]

This is not practical for low-latency gaming.

I don't recall VESA ever standardizing a specification that didn't work. I think it's pretty safe to assume that the VESA standards setting task group members know what they are doing. Especially considering that the people creating the spec work for the companies that are ultimately responsible for implementing the spec.

Nvidia even has a seat on the BOD.

It's an optional feature for 1.2a. Lack of support will be unavoidable.

 

[Mand]

I don't recall VESA ever standardizing a specification that didn't work. I think it's pretty safe to assume that the VESA standards setting task group members know what they are doing. Especially considering that the people creating the spec work for the companies that are ultimately responsible for implementing the spec.

Nvidia even has a seat on the BOD.


http://www.vesa.org/about-vesa/member-companies/

Granted.

But why hasn't AMD released...any technical information at all? All we have is some vague notion of "It can totally do that! Just wait and see!" I find that deeply unsatisfying.

If it's so open, why is AMD being so closed?

 

[monstercameron]

This is not practical for low-latency gaming.



It's an optional feature for 1.2a. Lack of support will be unavoidable.

how much latency do you think this would add to the pipeline for you to draw that conclusion?

 

[monstercameron]

Granted.

But why hasn't AMD released...any technical information at all? All we have is some vague notion of "It can totally do that! Just wait and see!" I find that deeply unsatisfying.

If it's so open, why is AMD being so closed?

that's there thing now -being secretive, doesn't have anything to do with whether or not a-sync works...

 

[SoulWager]

On the same line of reasoning, just because it hasn't been demoed in its final form doesn't mean it is impossible to implement.

No one said it was impossible to implement, but there's no reason to think existing eDP hardware is a workable solution, at least not until adaptation to changing framerates is shown.

 

[Phynaz]

Granted.

But why hasn't AMD released...any technical information at all? All we have is some vague notion of "It can totally do that! Just wait and see!" I find that deeply unsatisfying.

If it's so open, why is AMD being so closed?

You could ask Nvidia the same thing. Why aren't they talking about it? Has Nvidia ever released technical information about a VESA standard?

VESA isn't AMD, that's why AMD isn't talking about it.

Who ever said the VESA specs were open?

 

[sontin]

how much latency do you think this would add to the pipeline for you to draw that conclusion?

Because the GPU determines the update intervall of the eDP panel.
For that you need at least 3 additional buffers.

 

[monstercameron]

Because the GPU determines the update intervall of the eDP panel.
For that you need at least 3 additional buffers.

why?

 

[sontin]

why?

The GPU sets the new refresh cycle. For that it needs to know how long it tooks to render frame B after A.
So, when the GPU finished C, it can send A to the eDP panel and set the working time for frame B.

BTW: I'm still uncertain if an eDP can set to any undefinied refresh rate...

 

[Mand]

You could ask Nvidia the same thing. Why aren't they talking about it? Has Nvidia ever released technical information about a VESA standard?

VESA isn't AMD, that's why AMD isn't talking about it.

Who ever said the VESA specs were open?

AMD said FreeSync was and would be open, before Adaptive Sync became part of the VESA standard.

They never provided any information. They never provided a demo. They provided something they said was a demo, but wasn't actually a demo. Their big point during that demo, however, was to point out how mean it is of Nvidia to ask us to pay for the things they spend money and time developing, and that FreeSync would be open.

Except now it's been five months, and they've said precisely squat about it. Nothing. Nada. Zilch. We have no technical information whatsoever.

So much for open.

Nvidia, on the other hand, as a result of providing hardware, we have a pretty good understanding that G-Sync works as advertised. People have tested it thoroughly, evaluating it for a host of performance characteristics. To say that G-Sync is dead because someday, somehow, someone might come up with something that might be somewhat similar is preposterous.

AMD's entire position since CES has been overplaying their hand, making people think that a legit competitor to G-Sync is just around the corner. Only they've done absolutely nothing to substantiate that claim. They have no technical information. They have no demos. They have no announced hardware partnerships. They have no announced product inclusions.

They have nothing other than the hope that you won't buy an Nvidia card because of their bluffing.

 

[Phynaz]

Why do you keep talking about AMD? This thread is about Displayport Adaptive V-Sync.

Again, VESA <> AMD.

 

[Mand]

BTW: I'm still uncertain if a eDP can set to any undefinied refresh rate...

This is far from certain.

Current implemenation of refresh rate change via eDP is for power saving through panel self-refresh. PSR, though, cannot be used for Adaptive Sync. Why? It's right there in the name: self-refresh. This means that the panel updates itself with the existing information, rather than getting a new frame pushed by the GPU.

Telling your GPU to throw away frames in order to drop the framerate is fine when you don't need 60 FPS when checking your email while your laptop's battery is dying. It's completely incompatible with gaming.

The claim is that you can use some of the techniques involved in PSR to have the display do different update things, but that is a big, big, BIG step. It hasn't ever been demonstrated, just talked about in a "Yeah, I'm sure we can figure out a way to do that" way.

 

[Mand]

Why do you keep talking about AMD? This thread is about Displayport Adaptive V-Sync.

Again, VESA <> AMD.

Because AMD is the only reason Adaptive Sync exists. They're the ones who asked for it to be added to the spec, after G-Sync showed up and showed there was interest.

VESA is a passthrough.

If you want to know why I keep talking about AMD, read AMD's FAQ on the first page. It explains rather clearly their interest. One particular one stands out:

Q: How are DisplayPort&#8482; Adaptive-Sync and Project FreeSync different?

A: DisplayPort&#8482; Adaptive-Sync is an ingredient DisplayPort&#8482; feature that enables real-time adjustment of monitor refresh rates required by technologies like Project FreeSync. Project FreeSync is a unique AMD hardware/software solution that utilizes DisplayPort&#8482; Adaptive-Sync protocols to enable user-facing benefits: smooth, tearing-free and low-latency gameplay and video.

Note that they still haven't said what their "unique solution" is. Or what protocols it will use. Or, really, anything, other than what the benefits they hope to achieve are going to be - which are exactly the benefits that G-Sync is demonstrating and has done so for the past seven months.

Until AMD shows us the beef, this is nothing more than a stunt to spread FUD to prevent people from buying Nvidia GPUs to take advantage of G-Sync. Why would you, if something better and cheaper is coming soon? Well, maybe because 1) it probably won't be better 2) it may well not be cheaper and 3) it certainly isn't coming soon. Until AMD shows really anything at all to substantiate their optimism, I remain unconvinced.

 

[flash-gordon]

I do believe G-Sync is a more precise solution, as it's specifically created for this objective and has some brute force behind it.

Also, I do believe the A-Sync can get into the "good enough" situation to the point we don't perceive great differences between them. And, considering it's free and open, it's great!

One question: is eDP already in use in mobile phones or just notebooks? It looks like a good solution for energy saving...

 

[Despoiler]

I treat him as a source of great accuracy in regards to AMD's capabilities, but not so much as far as Nvidia's capabilities. Why is this unreasonable, exactly?

And, again, no, they did NOT show variable refresh in their demo. What they showed, and you can look for yourself since they posted the video, is two laptops with FIXED, STATIC refresh rates, that weren't varying. You keep repeating a claim that is directly contradicted by video evidence (the OSD of the laptops shows exactly what they're doing, one is running 30 FPS at 60 Hz vsync, the other is running 50 FPS at 50 Hz vsync).

You're right that we're waiting on the TCON, scaler, and monitor manufacturers to take it up. That's my whole, entire point. Adaptive sync does not yet exist. It has not been demonstrated that the eDP technique actually results in variable refresh. These are facts. I don't pretend to know what AMD is doing in its top secret internal research, but I do know they've never actually demonstrated variable refresh yet. The CES demo did not do it.

His job is to know everything about the industry, what is out there right now, and what is coming in the future. Competitors know everything about each others released products. The die shots are available to see exactly what is going on in the chip. I think it's a stretch on your part that he would be ignorant in this case. We can leave it at that.

The CES demo did show it working. Watch it again. The left laptop has v-sync enabled. The FPS changes slightly, but the frame time value ie the refresh rate does not move except for 1/100th increments about 3 times. The right shows the FPS and frame time changing rapidly by up to 1/10 increments. Neither is fixed, but both are syncing. It's not 50hz v-sync or you'd see the same as the left where the frame time is static only changing in the 1/100 value range. The only issue with the demo is the right laptop's render isn't complex enough to show large swings in FPS to make it as obvious as Nvidia's demo.

 

[Mand]

Yes, it's also used in mobile.