Hi, I reported a bug upstream @Plasma (https://bugs.kde.org/show_bug.cgi?id=365455) and KDE developers discovered the issue is in the Intel driver: the modesetting fails on the screen and that's why it goes off. I can trigger switching the display on by going through a dpms cycle. I have the very same issue with modesetting and with kernels from 4.4 to 4.7, so I'm not sure where the problem may be. In the linked bug report you can find logs and much more informations, including some videos. Please let me know if you need anything else, I'm at your disposal. Thanks, Niccolò
No one is willing to help?
Please try drm-intel-nightly branch of http://cgit.freedesktop.org/drm-intel. Please state your problem in this bug. Please add drm.debug=14 module parameter and attach dmesg from boot to the problem to this bug.
Created attachment 126647 [details] dmesg_drm.debug I have issues when turning on external monitors on miniDP MST: the "secondary" monitors of the MST setup doesn't turn on. I can turn it on by going through a dpms cycle (waiting for power management to set both screens into dpms mode, then move the mouse to exit dpms). Another way to turn the "secondary" monitor on is disabling and re-enabling it once again. I attached dmesg with drm.debug=14 and 4.8.0-1-drm-intel-nightly.
Do you still need more info? The very same problem happens when switching from a virtual terminal.
Anyone who can help me? This bug really prevents me from working efficiently because I can't use my multi monitor setup. I am willing to help in any way to track down the source of this bug and fix it. I'm removing the NEEDINFO status because I already provided everything you asked.
There's nothing in the dmesg log to indicate a failure when attempting to enable the second MST monitor. In fact there's indications that everything is OK and that modeset should be successful: [ 8.943531] [drm:drm_setup_crtcs] desired mode 3200x1800 set on crtc 26 (0,0) [ 8.943533] [drm:drm_setup_crtcs] desired mode 2560x1440 set on crtc 30 (0,0) [ 8.943534] [drm:drm_setup_crtcs] desired mode 2560x1440 set on crtc 34 (0,0) In the KDE bug you state the problem got worse with Plasma 5.8. Can you go into more details?
I understand that the logs say there is no failure, but still the secondary screen of the MST setup turns off and I have to go through a dpms cycle to turn it on again (which means waiting until power management turns off the screen and then moving the mouse to turn it on again). With Plasma 5.8 I also get another annoyance: if I start Plasma with my MST monitors attached it doesn't show the panel with the "start" menu. Except for that additional issue there are no differences with previous versions of Plasma. Also, if I start Plasma without my MST monitors attached and if I attach them later, the behaviour is exactly like the previous versions (it properly shows the panel with the "start" menu). Plasma developers insist that this is an Intel bug, the only thing I can do is downloading a Fedora 25 live cd and try if I have the same issue with Gnome. I will let you know soon.
It doesn't happen with Gnome on Fedora 25 beta, I will let Plasma developers know. Thanks.
It is definitely a bug on the Intel side: $ xrandr --output eDP1 --off --output DP1-1 --auto --output DP1-8 --auto xrandr: Configure crtc 1 failed Please let me know how can I help you to debug this.
$ xrandr --verbose --output eDP1 --off --output DP1-1 --auto --output DP1-8 --auto crtc 0: disable screen 0: 2560x1440 675x380 mm 96.25dpi crtc 1: 2560x1440 59.95 +0+0 "DP1-1" "DP1-8" xrandr: Configure crtc 1 failed crtc 0: disable crtc 1: disable crtc 2: disable crtc 3: disable screen 0: revert crtc 0: revert crtc 1: revert crtc 2: revert crtc 3: revert
Hello I just tried to reproduce the problem with following configuration: BDW NUC, using MST connected by mDP-DP with cable connected DP-DP. Attaching my configuration used to test ====================================== Software ====================================== kernel version : 4.12.0-rc3-drm-tip-ww22-commit-187376e+ architecture : x86_64 os version : Ubuntu 17.04 os codename : zesty kernel driver : i915 bios revision : 5.6 bios release date : 05/11/2017 ====================================== Graphic drivers ====================================== mesa : 17.0.3 modesetting : modesetting_drv.so xorg-xserver : 1.19.3 libdrm : 2.4.76 libva : 1.7.3-2 vaapi (intel-driver) : 1.7.3 cairo : 1.14.8-1 intel-gpu-tools : 1.17-1 ====================================== Hardware ====================================== platform : BDW motherboard id : NUC5i7RYB form factor : Desktop cpu family : Core i7 cpu family id : 6 cpu information : Intel(R) Core(TM) i7-5557U CPU @ 3.10GHz gpu card : Intel Corporation Iris Graphics 6100 (rev 09) (prog-if 00 [VGA controller]) memory ram : 15.58 GB max memory ram : 16 GB display resolution : 1600x900 cpu thread : 4 cpu core : 2 cpu model : 61 cpu stepping : 4 socket : Socket BGA1168 signature : Type 0, Family 6, Model 61, Stepping 4 hard drive : 111GiB (120GB) current cd clock frequency : 450000 kHz maximum cd clock frequency : 540000 kHz displays connected : DP-2 DP-4 DP-6 ====================================== Firmware ====================================== ====================================== kernel parameters ====================================== quiet splash fastboot drm.debug=0xe i did not have any issue. Works for me
Created attachment 132381 [details] kern.log
I confirm, I cannot reproduce the issue anymore since a couple of weeks.
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