DP hotplug/unplug behaves correctly across text console, VT switch to lightdm and login into Unity. There's still some WARNs in dmesg (attached) when connecting the external DP monitor, but nothing crashes, and my 4k desktop appears to function correctly:
[drm:skl_set_cdclk [i915]] *ERROR* failed to inform PCU about cdclk change
WARNING: CPU: 1 PID: 929 at /home/kernel/COD/linux/drivers/gpu/drm/drm_irq.c:1218 drm_wait_one_vblank+0x16f/0x1b0 [drm]
vblank not available on crtc 0, ret=-22
[drm:gen8_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
I can confirm that linux-image 4.7.0-994- generic_ 4.7.0-994. 201607052202 from http:// kernel. ubuntu. com/~kernel- ppa/mainline/ drm-intel- nightly/ 2016-07- 06/ behaves much better.
DP hotplug/unplug behaves correctly across text console, VT switch to lightdm and login into Unity. There's still some WARNs in dmesg (attached) when connecting the external DP monitor, but nothing crashes, and my 4k desktop appears to function correctly:
[drm: skl_set_ cdclk [i915]] *ERROR* failed to inform PCU about cdclk change
WARNING: CPU: 1 PID: 929 at /home/kernel/ COD/linux/ drivers/ gpu/drm/ drm_irq. c:1218 drm_wait_ one_vblank+ 0x16f/0x1b0 [drm]
vblank not available on crtc 0, ret=-22
[drm: gen8_irq_ handler [i915]] *ERROR* CPU pipe B FIFO underrun
Confirmed to still crash with http:// kernel. ubuntu. com/~kernel- ppa/mainline/ v4.7-rc6- yakkety/