Hello, I had the same issue and managed to get back to a sane situation
To summarize (more details below), the pattern I saw on my laptop is: - it works fine as long as the default screen configuration is used (that is, default screen resolution, default screen position) (actually, no log "switch to mode" in Xorg.0.log) - to work around the issue: I switched to vt1, waited for a while (maybe 30 seconds, I'm not 100% sure), switched back to vt7. Then the login screen was displayed and I was able to log in. - It works better after applying the default configuration using the System Settings (the login screen appears after a reboot) Installed packages: xserver-xorg-core 2:1.17.2-1ubuntu9 xserver-xorg-video-intel 2:2.99.917+git20150808-0ubuntu4 nvidia-355 355.11-0ubuntu0~gpu15.10.1 Hardware is Intel HD Graphics 4600 + NVIDIA GT740M [ 2.612] (--) PCI:*(0:0:2:0) 8086:0416:1043:122d rev 6, Mem @ 0xf7400000/4194304, 0xd0000000/268435456, I/O @ 0x0000f000/64 [ 2.612] (--) PCI: (0:1:0:0) 10de:1292:1043:122d rev 161, Mem @ 0xf6000000/16777216, 0xe0000000/268435456, 0xf0000000/33554432, I/O @ 0x0000e000/128, BIOS @ 0x????????/524288 Outputs are eDP1 (laptop's screen, 1600x900) and HDMI1 (1920x1080) (now they are named eDP-1-0 and HDMI-1-0... could be an update I applied) Xorg correctly loads the drivers, prime-offload correctly associates the cards. Then blank screen After some vt switches, the login screen appeared on vt7. The display was corrupted (only for a while), the screen resolution was unusual and I had the same display on both screens. The last vt switch likely matches the log at 67.771 (it's definitely an unusual resolution, with mirror mode) [ 3.460] (WW) config/udev: device ETPS/2 Elantech Touchpad already added. Ignoring. [ 3.808] (II) intel(G0): switch to mode 1600x900@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none [ 3.855] (II) intel(G0): switch to mode 1600x900@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none [ 4.646] (II) intel(G0): switch to mode 1920x1080@60.0 on HDMI1 using pipe 1, position (1600, 0), rotation normal, reflection none [ 34.168] (II) NVIDIA(0): Setting mode "NULL" [ 34.169] (II) intel(G0): switch to mode 1600x900@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none [ 34.169] (II) intel(G0): switch to mode 1920x1080@60.0 on HDMI1 using pipe 1, position (1600, 0), rotation normal, reflection none [ 34.256] (--) synaptics: ETPS/2 Elantech Touchpad: touchpad found [ 36.296] (II) NVIDIA(0): Setting mode "NULL" [ 36.297] (II) intel(G0): switch to mode 1600x900@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none [ 36.297] (II) intel(G0): switch to mode 1920x1080@60.0 on HDMI1 using pipe 1, position (1600, 0), rotation normal, reflection none [ 36.356] (--) synaptics: ETPS/2 Elantech Touchpad: touchpad found [ 64.086] (II) NVIDIA(0): Setting mode "NULL" [ 64.086] (II) intel(G0): switch to mode 1600x900@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none [ 64.086] (II) intel(G0): switch to mode 1920x1080@60.0 on HDMI1 using pipe 1, position (1600, 0), rotation normal, reflection none [ 64.176] (--) synaptics: ETPS/2 Elantech Touchpad: touchpad found [ 67.596] (II) XKB: reuse xkmfile /var/lib/xkb/server-53A4CFD27CBE694B87E57086754C176B71A8EEB5.xkm [ 67.771] (II) intel(G0): switch to mode 1440x900@59.9 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none [ 67.773] (II) intel(G0): switch to mode 1440x900@59.9 on HDMI1 using pipe 1, position (0, 0), rotation normal, reflection none Then I was able to log in and use xrandr to change the resolutions and position of the screens. I'm not certain, but I probably tried to change the configuration from the System Settings/Display tool, too. After a reboot the lightdm's login immediately appeared and I was able to log in. At this point, the logs "switch to mode" do not appear in Xorg.0.log anymore. The configuration is eDP-1-0 connected primary 1600x900+0+0 382mm x 215mm 1600x900 60.01*+ HDMI-1-0 connected 1920x1080+1600+0 521mm x 293mm 1920x1080 60.00*+ 50.00 59.94 HDMI-1-0 at the right of eDP-1-0 Then I tried to "invert" the screens (HDMI output left of eDP output) from the System Settings. After two attempts, the change was taken into account. After a reboot, the Xorg server started to segfault after the login. To fix: I switched to vt1, waited a few seconds, then switched back to vt7. Then I was able to log in (with the displays back to the original configuration - HDMI output at the right of eDP output) Then I applied the default display configuration using the System Settings. Now I can correctly log in, even after a reboot. However, at the moment, trying to use xrandr to change the display configuration crashes xorg. [ 195.951] (EE) [ 195.951] (EE) Backtrace: [ 195.951] (EE) 0: /usr/bin/X (xorg_backtrace+0x4e) [0x5615e28a462e] [ 195.951] (EE) 1: /usr/bin/X (0x5615e26f0000+0x1b8999) [0x5615e28a8999] [ 195.951] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7f3cdb36f000+0x352f0) [0x7f3cdb3a42f0] [ 195.951] (EE) 3: /usr/bin/X (DamageRegister+0x11) [0x5615e282b3a1] [ 195.951] (EE) 4: /usr/bin/X (0x5615e26f0000+0xd9ac8) [0x5615e27c9ac8] [ 195.951] (EE) 5: /usr/bin/X (BlockHandler+0x8a) [0x5615e274ccca] [ 195.951] (EE) 6: /usr/bin/X (WaitForSomething+0x163) [0x5615e28a1393] [ 195.951] (EE) 7: /usr/bin/X (0x5615e26f0000+0x57fa1) [0x5615e2747fa1] [ 195.951] (EE) 8: /usr/bin/X (0x5615e26f0000+0x5c34b) [0x5615e274c34b] [ 195.951] (EE) 9: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7f3cdb38fa40] [ 195.951] (EE) 10: /usr/bin/X (_start+0x29) [0x5615e27366c9] [ 195.951] (EE) [ 195.951] (EE) Segmentation fault at address 0x10 [ 195.952] (EE) Fatal server error: [ 195.952] (EE) Caught signal 11 (Segmentation fault). Server aborting -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1501041 Title: No visible display in ubuntu session when using nvidia drivers via nvidia-prime until screen goes to sleep, then waked up To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1501041/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
