[Bug 202445] New: amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[Bug 202445] New: amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

            Bug ID: 202445
           Summary: amdgpu/dc: framerate dropping below adaptive sync
                    range causes screen flickering
           Product: Drivers
           Version: 2.5
    Kernel Version: 5.0rc4
          Hardware: All
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Video(DRI - non Intel)
          Assignee: drivers_video-dri@kernel-bugs.osdl.org
          Reporter: libcg@protonmail.com
        Regression: No

linux 5.0rc4
mesa 4aa64940c
xf86-video-amdgpu a1b479c

hardware:
- R9 Fury
- Samsung C27HG70 (1020.0 firmware, Freesync Ultimate Engine)

I'm running the Unigine Valley benchmark extremely smoothly as long as the
framerate stays in between 48-144fps. When it drops below that, I'm observing
heavy stuttering and flickering in the darker parts of the image. The
flickering also affects the loading screen when frames are rendered very
infrequently.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #1 from Alex Deucher (alexdeucher@gmail.com) ---
Please attach your dmesg output and xorg log (if using X).

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #2 from Clément Guérin (libcg@protonmail.com) ---
Created attachment 280853
  --> https://bugzilla.kernel.org/attachment.cgi?id=280853&action=edit
dmesg output

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #3 from Clément Guérin (libcg@protonmail.com) ---
Created attachment 280855
  --> https://bugzilla.kernel.org/attachment.cgi?id=280855&action=edit
Xorg.1.log

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #4 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) ---
Below the range support didn't make it into 5.0. That patches for this are in
amd-staging-drm-next:

https://cgit.freedesktop.org/~agd5f/linux/log/?h=amd-staging-drm-next

They should show up in the next release I think.

Nicholas Kazlauskas

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #5 from Clément Guérin (libcg@protonmail.com) ---
Can you point me to the commits introducing this feature? Thanks.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #6 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) ---
Should be:

https://patchwork.freedesktop.org/series/53559/

"drm/amd/display: Add below the range support for FreeSync"

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #7 from Clément Guérin (libcg@protonmail.com) ---
Thanks. I'll try it out asap. I strongly feel that this feature should be
backported to 5.0 since the freesync implementation seems broken without it. I
understand if that's not possible.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #8 from Clément Guérin (libcg@protonmail.com) ---
Strange. It looks like this commit has been merged in the mainline kernel
before rc1.
https://github.com/torvalds/linux/commit/180db303ff466a3887c841e805568b92233e2d0e#diff-730f0f79c9b013ef9a2c68f236d473b0

This should be a legitimate bug then.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #9 from Clément Guérin (libcg@protonmail.com) ---
I just tested built `drm-next-5.1-wip` (8054c54a6), it's flickering/stuttering
as well.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #10 from Clément Guérin (libcg@protonmail.com) ---
I did some more testing today, using my monitor OSD to determine if freesync is
active. None of the Steam Play games I own work with freesync, the refresh rate
stays at 144Hz. It looks like freesync simply doesn't work with wine. That
includes:
- Alan Wake (DX9 -> OpenGL)
- DOOM (OpenGL)
- Fallout: New Vegas (DX9 -> OpenGL)
- Trackmania Stadium² (DX11 -> OpenGL)

Native games do seem to work, and I'm observing flickering with all of them.
Including:
- Getting Over It
- Kerbal Space Program
- Night in the Woods
- Rocket League
- Unigine Valley
- VVVVVV

In the case of KSP, I'm seeing flickering even though the framerate floats
around 80-90fps. Disabling VSYNC makes the flickering mostly disappear, but
it's still visible when microstuttering occurs. The monitor OSD displays a
wildly varying refresh rate with VSYNC ON, but seems rather stable with VSYNC
OFF.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #11 from Clément Guérin (libcg@protonmail.com) ---
Same issue with 5.0rc5.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #12 from Clément Guérin (libcg@protonmail.com) ---
Here's a video of the issue shot in 1080p60:
https://www.youtube.com/watch?v=yQmlqggF2I8 (sorry I had to make it vertical)

The game fps counter is on the upper right, and the monitor's is on the bottom
right. The flickering is visible in the video.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #13 from Clément Guérin (libcg@protonmail.com) ---
YouTube refuses to show the vertical video as 1080p so I made another one here,
this time horizontal: https://www.youtube.com/watch?v=CTKr4NWXXKI

Also for reference, here's Unigine Valley running on Windows with no flickering
and smooth LFC: https://www.youtube.com/watch?v=4mYbZ7leVPw Framerate on the
monitor OSD is much more consistent.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #14 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) ---
FreeSync not working on WINE is a Mesa issue I believe.

I don't think the backend WINE goes through is DRI3 which is required to use
the present extension / support page-flipping through X to DRM.

The flickering I'm not quite sure about. I don't think I've observed it
happening lately in amd-staging-drm-next on Raven or Vega when running any of
the Unigine benchmarks at varying settings (dipping below and into the VRR
range).

Do you mind booting with drm.debug=4 and posting a dmesg log when you're
running the Unigine Valley benchmark? It would also help to know what desktop
environment/compositor you're using.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #15 from Clément Guérin (libcg@protonmail.com) ---
Created attachment 280949
  --> https://bugzilla.kernel.org/attachment.cgi?id=280949&action=edit
dmesg drm.debug=4

Here's the dmesg output as requested. I'm running gnome-shell 3.30.2.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #16 from Clément Guérin (libcg@protonmail.com) ---
Nicholas, I found a TODO in the freesync btr code for pre-DCE12 GPUs
(pre-Vega?).
https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/amd/display/modules/freesync/freesync.c#L897

Could that be related?

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #17 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) ---
I can reproduce the issue but vsync needs to be on. I'd recommend turning vsync
off for now to avoid flickering.

The issue lies in how amdgpu_dm handles waiting for vblank and how userspace
interacts with the vblank counter in variable refresh rate mode.

The routine that does the wait / flip programming tries to aim for the next
vblank interval based on the current counter which rolls around at the vback
porch. If the routine gets delayed past scanout and into the front porch what
can happen is we're stuck waiting for the current vblank interval to timeout,
which will force the monitor to the lowest refresh rate and introduces
stuttering / flickering in this case.

There should be a fix for this soon.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #18 from Clément Guérin (libcg@protonmail.com) ---
Hi Nicholas, any progress on this?

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #19 from Clément Guérin (libcg@protonmail.com) ---
I just built drm-fixes-5.0 including
https://cgit.freedesktop.org/~agd5f/linux/commit/?h=drm-fixes-5.0&id=d63716658ac16c515d1223a9fbf5edbf76b1b333
and this issue remains.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #20 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) ---
That patch certainly helps for the case where the pageflip was submitted during
vblank (the frontporch will no longer timeout, causing flickering).

The video you recorded helped identify what I think is the specific issue in
this case though - I believe that the implementation is frequently changing the
BTR target instead or prioritizing the last used target rate.

There should be a fix for this coming soon, it should also apply to 5.0 once
it's done.

Thanks for the report!

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #21 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) ---
I'll let you know when it's up so you can try it. It should resolve the issue,
but if it doesn't it will at least help narrow down the cause.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #22 from Clément Guérin (libcg@protonmail.com) ---
Great news. Can you confirm that
https://bugzilla.kernel.org/show_bug.cgi?id=202445#c16 is not related to this
issue?

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #23 from Clément Guérin (libcg@protonmail.com) ---
Hi Nicholas, any progress on this? Can you answer my question above? Thanks.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #24 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) ---
I don't believe that it's related to the issue, but the patch below should help
with the issue:

https://patchwork.freedesktop.org/patch/292460/

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #25 from Clément Guérin (libcg@protonmail.com) ---
I tried this patch on top of linux 5.0.2 and it didn't help.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #26 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) ---
Was "drm/amd/display: Use vrr friendly pageflip throttling in DC." also in the
tree you built?

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #27 from Clément Guérin (libcg@protonmail.com) ---
I'm sorry, I assumed this particular commit had been backported to Linux 5.0,
and it's apparently not the case. I will try with both when I find some time
tonight.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #28 from Clément Guérin (libcg@protonmail.com) ---
Nevermind. This commit was merged right before 5.0 was released. So yes, it was
in the tree.

What I suspect is happening is that a couple or more frames are scheduled by
the BTR code, but for some reason they are displayed at the max refresh rate
(144Hz in my case), then the monitor times out on the last frame and that
produces flickering. Which is what I pointed out in comment 16.

EDIT: I just realized that the link in that comment is outdated because code
moved around. This is what it originally pointed to:
https://github.com/torvalds/linux/blob/672e78c/drivers/gpu/drm/amd/display/modules/freesync/freesync.c#L980

/* TODO: pass in flag for Pre-DCE12 ASIC
 * in order for frame variable duration to take affect,
 * it needs to be done one VSYNC early, which is at
 * frameCounter == 1.
 * For DCE12 and newer updates to V_TOTAL_MIN/MAX
 * will take affect on current frame
 */

As far as I know that will only affect pre-Vega GPUs, and I'm running Fiji.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #29 from Clément Guérin (libcg@protonmail.com) ---
Any progress on this?

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #30 from Clément Guérin (libcg@protonmail.com) ---
I just tested drm-next-5.2 with Mario Kleiner's VRR BTR patch series applied on
top: https://lists.freedesktop.org/archives/amd-gfx/2019-April/033470.html

The situation improved a lot. Unigine Valley is now smooth at low framerates
with some occasional flickering when the BTR limit is crossed. Rocket League
still flickers when the game stutters.

At this point I'm not sure if the bug is fully fixed or if it's just a hardware
limitation. Anyhow, it's good progress.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #31 from Nicholas Kazlauskas (nicholas.kazlauskas@amd.com) ---
With the third patch in that series the bug should be fixed (ncorrect IRQ
handling for older ASICs). I imagine it'll be merged soon.

You'll still likely see minor luminance flickering when you're going from a
relatively framerate (short front porch duration) to low framerate (long front
porch duration).

It depends on the panel characteristics for the display and supported VRR
range, however. Not all displays will exhibit the same luminance delta between
min and max front porch duration.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

jaapbuurman@gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jaapbuurman@gmail.com

--- Comment #32 from jaapbuurman@gmail.com ---
I am experiencing the exact same issue, although I am still running the 5.1
kernel. I feel uncomfortable compiling my own kernel, so I cannot test 5.2 just
yet. I do have an additional observation that might be useful for debugging. My
freesync monitor has a 48-144 freesync range, and displays the current refresh
rate on its OSD.

The issue for me is the easiest to reproduce in Kerbal Space program while in
space, since the flickering is especially visible with the many white stars on
the blackness of space.

While in space with a large vessel that pushes your FPS down (33-40 FPS in the
ingame FPS monitor), my monitor is rapidly oscillating through the entire
freesync range (as low as 48 and as high as 144, and everything in between). As
far as I understand the technology, whenever the FPS is stable (for example at
37), it should use LFC to display each frame twice or thrice, and the monitor
should refresh at a constant 74hz or 111hz. But that is not what is happening
if I use a static view with a constant 37 FPS.

Is there something I can do to rule out a monitor issue? Perhaps by setting
some kind of debug option to see what the driver is instructing the monitor to
do?

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #33 from Clément Guérin (libcg@protonmail.com) ---
It looks like the luminance flickering situation is much improved when using
linux 5.3 with this "LFC behaviour" patch applied:
https://lists.freedesktop.org/archives/amd-gfx/2019-September/039856.html

The easiest way to reproduce the problem is to play Kerbal Space Program, open
the Vehicle Assembly Building and then hover the mouse over the parts selector,
on the left of this screenshot:
https://www.kproplab.org/wp-content/uploads/2018/09/eex-1.png

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #34 from jaapbuurman@gmail.com ---
How big is the improvement? Is the issue completely gone, or is it still there?
The KSP example also reliably triggers the flickering for me, and I am using
the exact same monitor.

These LFC patches are going to be included in the 5.5 kernel, right? Or will
they be included in an earlier kernel version?

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #35 from Clément Guérin (libcg@protonmail.com) ---
If you haven't updated to linux 5.2 yet, you should because it fixed constant
flickering when in LFC mode.

This additional patch helps when freesync goes in and out of LFC mode. It's not
fully fixed, but the flickering is a lot less severe. According to the Phoronix
article it should indeed land in linux 5.5.

When compiling a kernel you should be able to install it next to the regular
one so you can't break your setup. I personally used the linux-mainline package
from the AUR and added the LFC patch on top.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #36 from Clément Guérin (libcg@protonmail.com) ---
If you haven't updated to linux 5.2 yet, you should because it fixed constant
flickering when in LFC mode.

This additional patch helps when the monitor goes in and out of LFC mode. It's
not fully fixed, but the flickering is a lot less severe. According to the
Phoronix article it should indeed land in linux 5.5.

When compiling a kernel you should be able to install it next to the regular
one so you can't break your setup. I personally used the linux-mainline package
from AUR and added the LFC patch on top.
-------- Original Message --------
On Sep 16, 2019, 06:22, wrote:

> https://bugzilla.kernel.org/show_bug.cgi?id=202445
>
> --- Comment #34 from jaapbuurman@gmail.com ---
> How big is the improvement? Is the issue completely gone, or is it still
> there?
> The KSP example also reliably triggers the flickering for me, and I am using
> the exact same monitor.
>
> These LFC patches are going to be included in the 5.5 kernel, right? Or will
> they be included in an earlier kernel version?
>
> --
> You are receiving this mail because:
> You reported the bug.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

Clément Guérin (libcg@protonmail.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |CODE_FIX

--- Comment #37 from Clément Guérin (libcg@protonmail.com) ---
An improved version of this patch landed in linux 5.6. I've been running GTA IV
with 5.6-rc1, this game is a total stutterfest but the luminance flickering was
minimal. It's good enough that I consider this issue fixed.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #38 from jaapbuurman@gmail.com ---
While I previously also had to same luminance flickering as you were describing
on older kernels, kernel 5.5 and unfortunately also 5.6 are showing me
flickering between a completely black screeb and the game itself in very rapid
succession. Not playable at all. I already considered it unplayable on older
kernels due to the rapidly changing brightness, but the current situation is
MUCH worse.

Anything I can do to help debug this issue?

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[Bug 202445] amdgpu/dc: framerate dropping below adaptive sync range causes screen flickering

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=202445

--- Comment #39 from jaapbuurman@gmail.com ---
To add to my previous comment: My ingame FPS is completely stable, yet my
monitor's HZ is jumping all over the place as can be seen from the monitor's
OSD. Previously, the luminance issue would only occur when the ingame FPS was
unstable.

-- 
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel