Bug 1332571

The same on my Lenovo T440s

Fedora23, 4.4.8-300.fc23.x86_64

Output of: /sbin/lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 0b)

working fine on Fedora 24.
T460p same specs except for CPU, Monitor attached to DP output of dockingstation.

Interestingly, contrary to Lenovo's documentation, the display outputs seem to be wired to the intel IGP, similar to the t460p without dedicated graphics.
The nvidia GPU is not going to be supported at all until kernel 4.7 I think.

output of 'xrandr --listproviders' with an external monitor attached via HDMI (I am at work):

Providers: number : 1
Provider 0: id: 0x49 cap: 0x3, Source Output, Sink Output crtcs: 3 outputs: 7 associated providers: 0 name:modesetting

lspci lists both cards though.

'xrandr --listproviders' docked with monitor connected:

Providers: number : 1
Provider 0: id: 0x49 cap: 0x3, Source Output, Sink Output crtcs: 3 outputs: 10 associated providers: 0 name:modesetting

relevant lspci lines:

00:02.0 VGA compatible controller: Intel Corporation HD Graphics 530 (rev 06)
02:00.0 3D controller: NVIDIA Corporation GM108M [GeForce 940MX] (rev a2)

Hitting same issue, Lenov T460p Core I7, Intel display card. 
Bios version: R07ET63W (2.03 ) ReleaseDate: 03/15/2016
There is a newer BIOS I'll update once I get a chance to do so. 

RHEL 7.2  CSB build.  
3.10.0-370.el7.rhel73drm.10.x86_64

lspci | grep vga 
00:02.0 VGA compatible controller: Intel Corporation Device 191b (rev 06)

xrandr --listproviders
Providers: number : 1
Provider 0: id: 0x4e cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 4 outputs: 11 associated providers: 0 name:Intel

running  #xrandr --auto   on my friends laptop (Lenov w541) fixes for this but not for me. 

At home I use a DPtoVGA adpator with an external screen it works fine. 
At office with docking VGA or DVI cable doesn't detect external screen, laptop keep in sleep mode while not used. 

If I restart the laptop docking screen is detected and works fine.

It's a new laptop this happened three times already. 
In two of the three cases I had connected the home screen with a DP. 
The DP port might be the reason this problem kicks in.

It wasn't the DP port after all. 
I'd set my laptop's lib to put laptop in sleep mode.
/etc/systemd/logind.conf
HandleSuspendKey=suspend

This caused my problems, after disabling it (default setting), external docking screen now works fine as before. 

Since then found a gnome ext to add sleep button on menu, rather than having to ctrl+power or have screen do it for me.

*********** MASS BUG UPDATE **************
 
We apologize for the inconvenience.  There is a large number of bugs to go through and several of them have gone stale.  Due to this, we are doing a mass bug update across all of the Fedora 23 kernel bugs.
 
Fedora 23 has now been rebased to 4.7.4-100.fc23.  Please test this kernel update (or newer) and let us know if you issue has been resolved or if it is still present with the newer kernel.
 
If you have moved on to Fedora 24 or 25, and are still experiencing this issue, please change the version to Fedora 24 or 25.
 
If you experience different issues, please open a new bug report for those.

*********** MASS BUG UPDATE **************
This bug is being closed with INSUFFICIENT_DATA as there has not been a response in 4 weeks. If you are still experiencing this issue, please reopen and attach the relevant data from the latest kernel you are running and any data that might have been requested previously.