Enabling AMD Radeon FreeSync On Linux 5.0

[tildearrow]

What good would freesync actually do for a desktop compositor? They can just sync with the monitors max refresh rate (aka vsync), no need for variable refresh rate.

Running windowed FreeSync applications, and avoiding mode-switch flicker when watching 25fps/30fps videos.

[DarkFoss]

Did anyone test it in KDE Wayland session?

I tried running Unigine Valley under plasma-wayland it almost competes before the x-server falls over and the x-server closes and restarts only useful(?) info left in the syslog is:

Mar  4 13:19:29 Tardis-1 kernel: [ 6045.669796] [drm:dc_link_detect [amdgpu]] *ERROR* No EDID read.
Mar  4 13:19:29 Tardis-1 kernel: [ 6045.938861] [drm] amdgpu_dm_irq_schedule_work FAILED src 11
Mar  4 13:19:29 Tardis-1 kernel: [ 6045.999448] kwin_wayland[29244]: segfault at 4 ip 00007faab092e2c5 sp 00007ffd77cba270 error 6 in libKF5WaylandServer.so.5.55.0[7faab08b8000+f2000]
Mar  4 13:19:29 Tardis-1 kernel: [ 6045.999454] Code: ff ff ff 7f 39 d6 75 09 83 ff 01 0f 86 94 00 00 00 48 63 d2 be 08 00 00 00 bf 08 00 00 00 e8 42 a2 fe ff 48 8b 7d 00 48 89 c3 <44> 89 68 04 48 63 47 04 48 8b 57 10 48 8d 34 17 44 39 e8 7c 03 49

If you use wayland I'd recommend not setting freesync/vrr always on by making a usr/share/X11/xorg.conf.d/10-freesync.conf and just use a command to play with it temporarily under regular plasma.

[juno]

In case you (or somebody on this forum) own a 144Hz monitor: Is FreeSync of 40-144Hz beneficial over plain 144Hz refresh rate? Does FreeSync result in less stuttering compared to plain 144Hz assuming the game is rendering frames at 40-80 FPS?

I've been using a 144 Hz FreeSync (35-90 or 56-144 range) monitor for 2 years.

Of course it is. High refresh rate and variable refresh rate solves different issues in different cases. Both clearly improve the user experience.

In your scenario, activating FreeSync results in either less stuttering or fixes tearing, depending on whether you use vertical sync right now.

[elovin]

Is there any information available about when FreeSync will be supported by RADV ?

Is LFC (low frequency compensation) also supported ?

[pal666]

Sorry but I'm not switching back to 16:9. I develop software primarily and extra height really makes a difference. And I love my Dell U2315.

just rotate monitor vertically. and buy larger one

[pal666]

What good would freesync actually do for a desktop compositor? They can just sync with the monitors max refresh rate (aka vsync), no need for variable refresh rate.

syncing at 60 hz does not work well for 24 fps movie. you show each movie frame either 2 or 3 monitor frames

[theriddick]

Freesync not only injects frames or prevents tearing, it smooths out apparent on screen performance, syncing frames better. If you have a game where fps jumps around like a mad squirrel (many) then it certainly is beneficial.

Sadly Linux isn't up to windows level of VRR support, not going to take a interest in it under Linux until someone fixes it up.

[pal666]

In case you (or somebody on this forum) own a 144Hz monitor:

i own 240 hz monitor, but i didn't test fs, fedora uses modesetting ddx by default and i feel lazy

Is FreeSync of 40-144Hz beneficial over plain 144Hz refresh rate?

yes. if your game needs 1/60 of second to generate frame, it will use 3 frames of monitor, i.e. 1/48 of second, i.e. worse than plain 60 hz monitor. freesync can give it 1/60 of second.

Does FreeSync result in less stuttering compared to plain 144Hz assuming the game is rendering frames at 40-80 FPS?

if there are no bugs in implementation (there was one fixed recently)

[chithanh]

My HP Envy x360 15-cp0001na with AU Optronics AUO22ED panel, was recognized as FreeSync capable 40 - 60 Hz on windows. But not on linux with kernel 5.0
xrandr --prop says vrr_capable: 0

Maybe I need to manually edit EDID data or something..

A post in the previous FreeSync thread noted similar issues on an Acer Nitro 5 (works on Windows, doesn't work on Linux). In the end, the EDID had to be modified.

https://www.phoronix.com/forums/forum/linux-graphics-x-org-drivers/open-source-amd-linux/1078289-amdgpu-fixes-for-linux-5-0-include-freesync-vrr-properties-for-edp-displays?p=1079597#post1079597

[Khrundel]

In case you (or somebody on this forum) own a 144Hz monitor: Is FreeSync of 40-144Hz beneficial over plain 144Hz refresh rate? Does FreeSync result in less stuttering compared to plain 144Hz assuming the game is rendering frames at 40-80 FPS?

No.
Vsync has two disadvantages over freesync: in case source can't catch display's refresh rate vsync adds additional lag, which is lesser than monitor's frame time and in that case it limits fps to half of monitor's refresh. In case of 144hz both these disadvantages are unnoticeable, you won't see less than 7ms lag and won't suffer from limiting fps to 72hz.
But there is one disadvantage of freesync over vsync: most of freesync monitors don't support adaptive overdrive. As you may know, all LCD matrices are slow like hell, especially when switching from gray to gray. To fix this, all monitors are using overdrive, instead of setting desired brightness of subpixel they set more contrast one, which results faster switching and masks slowness (half of frame time pixel is darker than desired and half of frame time is brighter). But this trick works well only when frame time is known. When using variable refresh rate monitor should adapt overdriving coefs to actual frame time. All gsync monitors have adaptive overdrive feature, nvidia requires this. For AMD this is optional.