Dear Maintainer,

After a recent upgrade sddm login is heavly flickering. it gets a white portion and then repaint the theme.

The screen stops flickering only after the username and password had
been entered.

No flickering happen after plasma is loaded (KDE screen) , or in
differet VT.

the flickering comes back if a new session is open via plasma that start
sddm login screen on a different VT.

I have tried Maldivians and breeze themes (both have the same issue).

There are reports in Gentoo forms that suggested to have libdrm2.4.80
but I have ibdrm2_2.4.84-2_amd64.deb installed.

extra details :
   4.13.0-1-amd64
   plasmashell 5.10.5
01:05.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RS482M [Mobility Radeon Xpress 200]

egrep "WW|EE" Xorg.0.log
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[  1177.153] (WW) The directory "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType" does not exist.
[  1177.153] (WW) Hotplugging is on, devices using drivers 'kbd', 'mouse' or 'vmmouse' will be disabled.
[  1177.153] (WW) Disabling Mouse0
[  1177.153] (WW) Disabling Keyboard0
[  1178.375] (WW) Falling back to old probe method for fbdev
[  1178.392] (WW) Falling back to old probe method for vesa

I have seen many errors such as the next in .xsession_errors (per logged user):
file:///usr/lib/x86_64-linux-gnu/qt5/qml/QtQuick/Controls/Button.qml:99: TypeError: Cannot read property 'width' of null
file:///usr/lib/x86_64-linux-gnu/qt5/qml/QtQuick/Controls/Button.qml:99: TypeError: Cannot read property 'width' of null
file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/views/Panel.qml:83: TypeError: Cannot read property 'Layout' of null
file:///usr/lib/x86_64-linux-gnu/qt5/qml/QtQuick/Controls/Styles/Base/ButtonStyle.qml:153:31: QML Item: Binding loop detected for property "implicitWidth"
KGlobal::locale(): Warning your global KLocale is being recreated with a valid main component instead of a fake component, this usually means you tried to call i18n related functions before your main component was created. You should not do that since it most likely will not work
ksmserver: autostart service ("/usr/bin/kmixctrl", "--restore") finished with exit code  0

KGlobal::locale(): Warning your global KLocale is being recreated with a valid main component instead of a fake component, this usually means you tried to call i18n related functions before your main component was created. You should not do that since it most likely will not work
org.kde.plasma: invalid fallback path in  ""

Hello.

I can confirm this behavior on an IBM ThinkPad T42 with Radeon graphics.

martin@shambhala:~> lspci -nn | grep VGA
01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/
ATI] RV350/M10 / RV360/M11 [Mobility Radeon 9600 (PRO) / 9700] [1002:4e50]

For me it appears to be related to

Flickering ATI X1300 r300 Mesa 17.2
https://github.com/sddm/sddm/issues/898

However disabling vsync for r300 driver did not help. I tried it via .drirc in
/root and in /var/lib/sddm like this:

<driconf>
    <device screen="0" driver="r300">
        <application name="Default">
            <option name="vblank_mode" value="0" />
        </application>
    </device>
</driconf>

I also tried "dri2" as driver name.

Thanks,

Dear Maintainer,

A workaround for this issue is to add Option "TearFree" "on" in xorg.conf for radeon
drivers. It doesn't solve the issue just hide it.