Bug 108832

Summary: Cursor flickering on switching between cursor types
Product: xorg Reporter: marlock9
Component: Driver/AMDgpuAssignee: xf86-video-ati maintainers <xorg-driver-ati>
Status: RESOLVED FIXED QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium CC: marlock9
Version: git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description marlock9 2018-11-22 14:03:47 UTC 
Copy of https://bugs.kde.org/show_bug.cgi?id=400097

Creating bug here because with help of KDE developer I have investigated it is amdgpu bug.

For example, I'm moving cursor arrow on text. Before it turns to "I" for text selecting I clearly see the intermediate cursor texture (can't see what type is it) located right or left from current cursor position. Same when I moving cursor arrow to the border of screen to resize. It looks like glitch or flickering.

It's lasting for about 2 years on different distributions.

https://drive.google.com/file/d/1bV7okri0I95tkCOqo-6Z-axnN3-BXk9U/view?usp=sharing

Above is link to a slo-mo video. You can clearly see what's happening when I'm moving cursor straight down from text:
1. "I" cursor
2. Arrow cursor appears 5 px left from "I" cursor
3. Arrow cursor leaps to the 15 px right-down diagonal

On the monitor it looks like flickering jumping of cursor.

amdgpu 18.0.1
libdrm-amdgpu1 2.4.91
linux 4.19.0
Radeon RX 570.

So, kde developer said:

"The issue is very likely in the video drivers, possibly not correctly syncronizing cursor position and cursor shape updates. I suggest to report it to the developers of your video drivers (your distribution might help to locate these)."

Finally, I have some experiments with video driver settings and I have no issues with such options in 20-amdgpu.conf:

Option "SWcursor" "true"
Option "TearFree" "true"

Truly said, only enabling SWcursor is enough for get rid of this bug but right after appears so much tearing (due to "KMS Pageflipping: disabled because of SWcursor" I suggest) so I needed to enable TearFree.
Comment 1 Dieter Nützel 2018-11-22 14:19:56 UTC 
Maybe duplicate of Bug #106175.

Can you please verify if patch from comment #55,
attachment 142558 [details] [review] solve it?
Comment 3 marlock9 2018-11-24 07:04:38 UTC 
Hello all!

(In reply to Michel Dänzer from comment #2)
> Does
> https://gitlab.freedesktop.org/daenzer/xf86-video-amdgpu/commits/cursor-
> double-buffer fix it?

Yes, it does.


(In reply to Dieter Nützel from comment #1)
> Maybe duplicate of Bug #106175.
> 
> Can you please verify if patch from comment #55,
> attachment 142558 [details] [review] [review] solve it?

I will reply some time later. But don't you think that restoring old behaviour (as far as I understand, this is exactly what is happening) is a dirty workaround?
Comment 4 marlock9 2018-11-24 13:35:33 UTC 
(In reply to Dieter Nützel from comment #1)
> Maybe duplicate of Bug #106175.
> 
> Can you please verify if patch from comment #55,
> attachment 142558 [details] [review] [review] solve it?

Finally I have recompile amdgpu module with this patch. This is not solving my issue, flickering still present, but I notice smoothness of pointer movement.
Comment 5 Michel Dänzer 2018-11-27 16:32:48 UTC 
Merge request submitted for review: https://gitlab.freedesktop.org/xorg/driver/xf86-video-amdgpu/merge_requests/14
Comment 6 Michel Dänzer 2018-12-13 11:45:49 UTC 
The fix is now merged, thanks for the report and testing.

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