Bug#947073: sddm: 100 % CPU usage when waiting for logon

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

Package: sddm
Version: 0.18.0-1
Severity: normal

Dear Maintainer,

I am running sddm with sddm-theme-breeze. When the system is idle
command top
shows:

  PID USER %CPU  %MEM     TIME+ COMMAND
  785 sddm 25.5  12.7  24:06.48 llvmpipe-0
  786 sddm 25.5  12.7  24:05.31 llvmpipe-1
  788 sddm 25.5  12.7  24:06.56 llvmpipe-3
  787 sddm 25.2  12.7  24:03.97 llvmpipe-2
  781 sddm  0.3  12.7   0:43.94 sddm-greeter

So a whole CPU core is loaded with what? Essentially doing nothing. Just
waiting for a user to type in his password.

Waiting for an event should not load the CPU at all.

Using 250 MiB of RAM waiting for a password entry is also unexpected.

Best regards

Heinrich

-- System Information:
Debian Release: 10.2
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: arm64 (aarch64)

Kernel: Linux 4.19.0-6-arm64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) (ignored:
LC_ALL set to en_US.UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
(ignored: LC_ALL set to en_US.UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages sddm depends on:
ii  adduser                 3.118
ii  debconf [debconf-2.0]   1.5.71
ii  libc6                   2.28-10
ii  libgcc1                 1:8.3.0-6
ii  libpam0g                1.3.1-5
ii  libqt5core5a            5.11.3+dfsg1-1+deb10u1
ii  libqt5dbus5             5.11.3+dfsg1-1+deb10u1
ii  libqt5gui5              5.11.3+dfsg1-1+deb10u1
ii  libqt5network5          5.11.3+dfsg1-1+deb10u1
ii  libqt5qml5              5.11.3-4
ii  libqt5quick5            5.11.3-4
ii  libstdc++6              8.3.0-6
ii  libsystemd0             241-7~deb10u2
ii  libxcb-xkb1             1.13.1-2
ii  libxcb1                 1.13.1-2
ii  qml-module-qtquick2     5.11.3-4
ii  x11-common              1:7.7+19
ii  xserver-xorg [xserver]  1:7.7+19

Versions of packages sddm recommends:
ii  haveged                         1.9.1-7
ii  libpam-systemd                  241-7~deb10u2
ii  sddm-theme-breeze [sddm-theme]  4:5.14.5.1-1

Versions of packages sddm suggests:
ii  libpam-kwallet5           5.14.5-1
pn  qtvirtualkeyboard-plugin  <none>

-- debconf information:
* shared/default-x-display-manager: sddm
  sddm/daemon_name: /usr/bin/sddm