After upgrade to 15.10, suspend request does not suspend

[Skewray]

(Ubuntu-bug wants a package, and I didn't know what to choose)

Suspend worked fine under 15.04. After upgrading to 15.10, requesting a suspend (from the lxde menu) blanks the screen except for a blinking underline in the upper left corner. The machine is otherwise unresponsive and requires a power-button reset.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: lxpanel 0.8.1-1ubuntu2
ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3
Uname: Linux 4.2.0-16-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.19.1-0ubuntu4
Architecture: amd64
Config_Home_LXDE:
 [Command]
 Logout=lxde-logout
CurrentDesktop: LXDE
Date: Thu Oct 29 09:41:20 2015
InstallationDate: Installed on 2015-08-14 (75 days ago)
InstallationMedia: Xubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422.1)
ProcEnviron:
 LANGUAGE=en_US
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 SHELL=/bin/tcsh
SourcePackage: lxpanel
UpgradeStatus: Upgraded to wily on 2015-10-28 (0 days ago)