Mesa RadeonSI Lands FreeSync / Adaptive-Sync Support That Pair With Linux 4.21

[Brisse]

Why aren't those monitors able to handle a 0...144 Hz range? I thought that besides avoiding overlapping images, another target is to reduce power consumption when nothing happens on the screen?

LCD has physical limitations to what it can do. If pixels are not refreshed then they turn black and if the refresh rate it too low then the display will flicker. There is a feature called low frame-rate compensation (LFC) that helps with this. It is able to output the same frame several times if the frame-rate is below the displays minimum which effectively divides the minimum refresh rate with three, so in my case of 44-120Hz, Freesync is actually working within 14.7-120fps which is more than adequate. Note that this feature only works on displays where the maximum refresh rate is at least 2.5 times higher than the minimum which pretty much disqualifies all 60hz monitors right off the bat. It only works on high refresh rate displays.

As for power consumption, you can see some measurements at different refresh rates in the TFT-central review I linked in my earlier post. For a desktop use case it's not really something worth talking about because the power savings are fairly insignificant, but for mobile devices it can be worthwhile.

[agd5f]

The ddx patches were merged a while ago:

https://gitlab.freedesktop.org/xorg/driver/xf86-video-amdgpu/merge_requests/5

[M@GOid]

LCD has physical limitations to what it can do. If pixels are not refreshed then they turn black and if the refresh rate it too low then the display will flicker. There is a feature called low frame-rate compensation (LFC) that helps with this. It is able to output the same frame several times if the frame-rate is below the displays minimum which effectively divides the minimum refresh rate with three, so in my case of 44-120Hz, Freesync is actually working within 14.7-120fps which is more than adequate. Note that this feature only works on displays where the maximum refresh rate is at least 2.5 times higher than the minimum which pretty much disqualifies all 60hz monitors right off the bat. It only works on high refresh rate displays.

As for power consumption, you can see some measurements at different refresh rates in the TFT-central review I linked in my earlier post. For a desktop use case it's not really something worth talking about because the power savings are fairly insignificant, but for mobile devices it can be worthwhile.

This.

Anyone considering a Freesync monitor must get one with LFC, otherwise you are wasting money. LFC will smooth a game when it is below the Freesync range. People say it is like getting a more powerful GPU, since your game will stay smooth in a longer FPS range.

[dungeon]

agd5f

Is there scaling mode implemented in amdgpu like on radeon? If i try to do it, got nothing

xrandr --output DVI-D-0 --set "scaling mode" "Full aspect"

Sounds like unimplemented or maybe it is a bug.

On radeon it is kind of buggy, scramble picture in some modes so i hoped this works better on amdgpu, but nothing

edit: OK it is DVI-0 on radeon while DVI-D-0 on amdgpu, but anyway does nothing on amdgpu.

[agd5f]

agd5f

Is there scaling mode implemented in amdgpu like on radeon? If i try to do it, got nothing

xrandr --output DVI-0 --set "scaling mode" "Full aspect"

Sounds like unimplemented or maybe it is a bug

It's implemented. Are you using X or wayland? What does `xrandr --verbose` show you for properties?

[dungeon]

X used, this is on Kabini so CIK forced, maybe it is that?

It says as how it is enabled for DVI:

scaling mode: Full aspect
supported: None, Full, Center, Full aspect

Default is None and i wanna Full aspect. And it says there Full aspect, but nothing happens really. Screen does not blink like on radeon when i enter that command It seems like it just change text there, but does nothing

[agd5f]

X used, this is on Kabini so CIK forced, maybe it is that?

It says as how it is enabled for DVI:


But nothing happens really, screen does not blink like on radeon when i enter that command It seems like it just change text there, but does nothing

Are you using a non-native mode? You won't see any change unless you've selected a non-native mode. E.g., trying to run 1024x768 on a 1920x1080 display.

[dungeon]

THat is what i did, also tried variuos resolutions all from EDID first and else and it do nothing really.

When i enter that command using radeon driver screen goes black for a moment while changing this (and that is expected), while on amdgpu nothing happens there (beside changing text in properties OK)

When i boot on radeon driver this works, while if i boot amdgpu nope.

Anyway i am not satisified how this works even on radeon, most modes are just kind of scrambled, like they have sort of scanlines or something, so i hoped on amdgpu it works better, but got nothing instead... so to me this is unusable on both really

I could only be nostalgic how this worked beautifully on FGLRX and DAL2

[dungeon]

Well this is great to read. But now I'll have to spend a extra to get a good freesync monitor. Any info of if it will include the HDR that is required for Freesync 2 ?
Hopefully Freesync makes it in time for Ubuntu 19.04

When i count number of FreeSync monitors...

https://www.amd.com/en/products/freesync-monitors

... and all of their differences i only imagine large team being busy

[pete910]

@shmerl

I have one of these https://www.samsung.com/us/computing...c32hg70qqnxza/

FS2
144hz
VA pannel

To be fair next to my IPS it's just as good, a very slight edge to the IPS.

Not cheap though.