Bug 100765

Summary: [DP] [SKL] DPMS: monitor turns on and off instead of suspending with DisplayPort
Product: DRI Reporter: Kenneth Heafield <freedesktop>
Component: DRM/IntelAssignee: Intel GFX Bugs mailing list <intel-gfx-bugs>
Status: CLOSED NOTOURBUG QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: normal    
Priority: medium CC: intel-gfx-bugs
Version: DRI git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard: ReadyForDev
i915 platform: SKL i915 features: display/DP
Description Flags
dmesg with drm.debug=0x1e log_buf_len=1M none

Description Kenneth Heafield 2017-04-23 20:52:22 UTC
Created attachment 130992 [details]
dmesg with drm.debug=0x1e log_buf_len=1M

-- system architecture: x86_64
-- kernel version: 4.11.0-rc7+ (from drm-tip commit bc781a3cf9a80e4c5ed0d47fd0c67923bcfcdf2c), same happens with 4.10.11
-- Linux distribution: Gentoo
-- Machine or mother board model: Gigabyte Z170X-Gaming 7 rev 1.0 (includes Alpine Ridge) and Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz
-- Display connector: DP
-- Monitor: Samsung LU28E590DS/EN

When the monitor is meant to be off with DPMS, it instead alternates between backlight off and backlight on every few seconds.  When the backlight is on, the monitor's OSD says "DisplayPort" in the top left as if it's just been connected.  

If done from X with "xset dpms force off", the screen is black except for the "DisplayPort" indicator.  If done from the console with "setterm -blank force", then the console appears when the backlight alternates to on.  This is not caused by input; it works fine with HDMI.  


Motherboard    | Distro       | Connection       | Monitor | Result
Z170X-Gaming 7 | Gentoo       | DisplayPort      | Samsung | Alternates
Z170X-Gaming 7 | Gentoo       | USBC->DisplayPort| Samsung | Alternates
Z170X-Gaming 7 | Gentoo       | HDMI 2.0         | Samsung | Correct
Z170X-Gaming 7 | Gentoo       | DisplayPort->DVI | Sceptre | Correct
Z170X-Gaming 7 | Gentoo       | USBC->VGA        | Sceptre | Correct
Z170X-UD5 TH   | Ubuntu 16.10 | USBC->DisplayPort| Samsung | Correct

USBC connection means the Thunderbolt Type C port with an adapter.    

The baseline monitor is a Sceptre X24WG-1080P with VGA and DVI inputs.  

Alternates is the problem that the monitor backlight turns on and off every few seconds.  Correct means the backlight stays off.  

Relevant piece of xrandr --verbose:

DP3 connected 3840x2160+0+0 (0x4a) normal (normal left inverted right x axis y axis) 610mm x 350mm
        Identifier: 0x45
        Timestamp:  32595
        Subpixel:   unknown
        Gamma:      1.0:1.0:1.0
        Brightness: 1.0
        Clones:     HDMI2
        CRTC:       0
        CRTCs:      0 1 2
        Transform:  1.000000 0.000000 0.000000
                    0.000000 1.000000 0.000000
                    0.000000 0.000000 1.000000
        Broadcast RGB: Automatic 
                supported: Automatic, Full, Limited 16:235
        audio: auto 
                supported: force-dvi, off, auto, on
        link-status: Good 
                supported: Good, Bad
  3840x2160 (0x4a) 533.250MHz +HSync -VSync *current +preferred
        h: width  3840 start 3888 end 3920 total 4000 skew    0 clock 133.31KHz
        v: height 2160 start 2163 end 2168 total 2222           clock  60.00Hz
Comment 1 Elizabeth 2017-06-21 16:34:16 UTC
Adding tag into "Whiteboard" field - ReadyForDev
*Status is correct
*Platform is included
*Feature is included
*Priority and Severity correctly set
*Logs included
Comment 2 Ricardo Madrigal 2017-06-30 17:13:34 UTC

I just tried to reproduce the problem with following configuration:

KBL NUC, using mini-DP to DP and HDMI - HDMI with 2 external monitor (acer) 3840 x 2160.

Attaching my configuration used to test

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               : 5.12
bios release date           : 09/12/2016

        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

platform                   : KBL-Nuc
motherboard model          : MS-B142
motherboard id             : MS-B1421
form factor                : Desktop
manufacturer               : Micro-StarInternationalCo.,Ltd.
cpu family                 : Core i7
cpu family id              : 6
cpu information            : Intel(R) Core(TM) i7-7500U CPU @ 2.70GHz
gpu card                   : Intel Corporation Device 5916 (rev 02) (prog-if 00 [VGA controller])
memory ram                 : 7.65 GB
max memory ram             : 64 GB
display resolution         : 1600x900
cpu thread                 : 4
cpu core                   : 2
cpu model                  : 142
cpu stepping               : 9
socket                     : Other
signature                  : Type 0, Family 6, Model 142, Stepping 9
hard drive                 : 111GiB (120GB)
current cd clock frequency : 540000 kHz
maximum cd clock frequency : 675000 kHz
displays connected         : DP-1 HDMI-A-2

dmc fw loaded             : yes
dmc version               : 1.1
guc fw loaded             : NONE
guc version wanted        : 0.0
guc version found         : 0.0

             kernel parameters
quiet splash fastboot drm.debug=0xe

I tried to reproduce this issue but i was unable to get it.
Actually this configuration works for me.
Comment 3 Kenneth Heafield 2017-06-30 20:47:53 UTC
Can I convince you to test this with a Samsung monitor?  The people over at NVIDIA had a very similar problem: https://devtalk.nvidia.com/default/topic/968059/dpms-not-working-with-displayport-monitor/

In particular, I'm not convinced that:

- Different processor line (KBL vs SKL)
- Different motherboard
- Different monitor

counts as "this configuration."  

I could bring it into work, where I am 40% funded by Intel and work closely with the pathfinding group and Altera, but they're probably not the right people to debug graphics drivers.
Comment 4 Elizabeth 2017-08-24 16:38:25 UTC
Hello Kenneth, 
Thanks for your patient. Could you please try to reproduce with latest drm-tip or vanilla mainline: https://cgit.freedesktop.org/drm-tip, https://www.kernel.org/.
From 4.12 and up, some DP patches that may help with this problem were added.
Comment 5 Kenneth Heafield 2018-01-25 21:41:16 UTC
Experiment 1. Send the monitor in to Samsung for repair.  Result: came back with longer pauses between turning on and off but still has the same fundamental problem.  

Experiment 2. Connect returned monitor to Dell XPS 113 9360 (Kaby Lake) via type-C to DisplayPort.  Result: works correctly.  

Experiment 3. Vanilla 4.14.13 from kernel.org with Gigabyte Z170X-Gaming G7 revision 1.0.  Still has the alternating issue when connected to DisplayPort from the motherboard or a type-C to DisplayPort adapter.  

Experiment 4. Buy a type-C to HDMI 2.0 cable and connect it to the monitor's HDMI input.  Power management works.  xrandr identifies the monitor as DP-2.  

So in the end DPMS via DisplayPort is still broken with this Samsung monitor.  But I have a configuration that works (type-C to HDMI cable).  

I suspect my Gigabyte Z170X-Gaming 7 rev 1.0 motherboard is slightly broken.  Additional evidence from this is that the HDMI output directly from the motherboard blanks on random occasions.  Which is why I started trying to use DisplayPort in the first place.
Comment 6 Jani Saarinen 2018-03-29 07:11:38 UTC
First of all. Sorry about spam.
This is mass update for our bugs. 

Sorry if you feel this annoying but with this trying to understand if bug still valid or not.
If bug investigation still in progress, please ignore this and I apologize!

If you think this is not anymore valid, please comment to the bug that can be closed.
If you haven't tested with our latest pre-upstream tree(drm-tip), can you do that also to see if issue is valid there still and if you cannot see issue there, please comment to the bug.
Comment 7 Jani Saarinen 2018-04-23 09:47:12 UTC
Seems like not driver issue? 
Closing, please re-open if still occurs or seeing closed wrongly.

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