Comme=
nt # 53
on bug 10617=
5
from bmilreu@gmail.co=
m
(In reply to rropid from comment #45)
> (In reply to bmilreu from comment #43)
> > If devs want an easy test case, use these links for reproducing i=
t in
> > chromium:
> >=20
> > https://www.vsynctester.=
com/
> > https://www.testufo.com=
/photo
> > https://www.slither.io
> >=20
> > move the cursor around, move/resize some windows. you will notice=
it
> >=20
> > the vsync/cursor stutters and frame-skips are pretty noticeable w=
ith dc=3D1 on
> > all three links
> >=20
> > KWin, compton, TearFree, mutter, xfwm4 all have the same problems.
>=20
> I just tried dc=3D1 and I only seem to have a problem if I use TearFre=
e.
> Things are totally fine without TearFree.
>=20
> To be clear about what I'm doing here right now:
>=20
> I made sure DC is enabled:
>=20
> $ systool -vm amdgpu | grep dc
> dc =3D "1"
> $ dmesg | grep -i display
> [ 1.014297] [drm] Display Core initialized with v3.1.59!
>=20
> I removed TearFree from my X config:
>=20
> $ cat /etc/X11/xorg.conf.d/20-amdgpu.conf=20
> Section "OutputClass"
> Identifier "my amdgpu settings"
> MatchDriver "amdgpu"
> Option "DRI" "3"
> EndSection
>=20
> And I started Compton like this to make sure it's a clean config:
>=20
> $ compton --config /dev/null --backend glx --vsync opengl
>=20
> With this setup, I don't seem to have any stutter. I visited the websi=
tes
> you mention in a Chromium window, then opened another window and tried
> moving things around and resizing. It behaves fine, same as what I kno=
w from
> normally using dc=3D0.
>=20
> Kernel is 4.19.2, Mesa 18.2.4, Xorg 1.20.3, the GPU is a RX480, monito=
r is
> 60 Hz.
>=20
> After I had typed this, I have now added TearFree to the X config and
> restarted X:
>=20
> $ cat /etc/X11/xorg.conf.d/20-amdgpu.conf=20
> Section "OutputClass"
> Identifier "my amdgpu settings"
> MatchDriver "amdgpu"
> Option "TearFree" "true"
> Option "DRI" "3"
> EndSection
>=20
> Now, with TearFree enabled, things are super terrible. Trying to move a
> window around has extreme stutter, it seems to drop frames. If I resta=
rt
> Compton with "GALLIUM_HUD=3Dfps" and then try moving a windo=
w around in
> circles, I can see it stays below 40 fps instead of hitting the 60 fps=
that
> it should be running at.
"compton --vsync opengl" is a case less/not affected by this in m=
y setup, try
--vsync opengl-swc, --vsync opengl-oml or --vsync opengl-mswc
Also try other compositors. Kwin, mutter, xfwm4