Display manager shows only a black screen

[Fibonacci]

I've noticed that, since the update to kernel 3.19.0-23, SDDM only shows a black screen instead of the usual login screen. It, however, works flawlessly on 3.19.0-22.

I've also noticed that the nvidia module is absent from lsmod in 3.19.0-23 onwards, but present in 3.19.0-22, and that is likely related, since I use nVidia GeForce GTS 250 graphics.

Additionally, I've tried kernels from http://kernel.ubuntu.com/~kernel-ppa/mainline/ and have noticed that versions 4.0 onwards fail in exactly the same way I described, while 3.19.8 (the latest available 3.xx) works fine.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: linux-image-3.19.0-25-generic 3.19.0-25.26
ProcVersionSignature: Ubuntu 3.19.0-25.26-generic 3.19.8-ckt2
Uname: Linux 3.19.0-25-generic x86_64
ApportVersion: 2.17.2-0ubuntu1.1
Architecture: amd64
Date: Fri Jul 31 11:37:05 2015
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=7e89a62d-4e77-40fc-89ba-42c3b1e76fc0
InstallationDate: Installed on 2015-07-13 (18 days ago)
InstallationMedia: Kubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
IwConfig:
 eth0 no wireless extensions.

 lo no wireless extensions.
ProcFB:

ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-3.19.0-25-generic root=UUID=0e051a2e-be67-40a6-8d32-29d4de69aca1 ro rootflags=subvol=@ quiet splash
RelatedPackageVersions:
 linux-restricted-modules-3.19.0-25-generic N/A
 linux-backports-modules-3.19.0-25-generic N/A
 linux-firmware 1.143.2
RfKill:

SourcePackage: linux
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/04/2012
dmi.bios.vendor: Intel Corp.
dmi.bios.version: BLH6710H.86A.0160.2012.1204.1156
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: DH67BL
dmi.board.vendor: Intel Corporation
dmi.board.version: AAG10189-206
dmi.chassis.type: 3
dmi.modalias: dmi:bvnIntelCorp.:bvrBLH6710H.86A.0160.2012.1204.1156:bd12/04/2012:svn:pn:pvr:rvnIntelCorporation:rnDH67BL:rvrAAG10189-206:cvn:ct3:cvr:

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream stable kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.19 stable kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.19.8-ckt4-vivid/

[Fibonacci (fibonacci-prower)]

Works fine on v3.19.8-ckt4, still fails on 4.xx and on v3.19.0-23.