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I'm new to the Linux world as I just switched from Windows for better web development environment. I have clean installed the Ubuntu 17.10 on my Lenovo X1 Carbon (4th Gen).

Overall setup:

I have connected 3 Dell U2414h monitors in a daisy-daisy chain. Display_1 and Display_2 have "DisplayPort 1.2" Enabled.

Problem:

  1. Displays can't be arranged from "Setting > Devices > Displays > Display Arrangement" UI. They seem to automatically re-arrange if I change the Orientation. Workaround would probably be to just physically re-arrange the monitors on my desk but still - is it normal that the re-arrangement doesn't work? Note: at first I installed 16.04 where the re-arrangement worked just fine for the same setup but had issues with BT devices.

  2. Displays are flickering randomly (not a certain but all of the monitors, not at the same time tho). In addition to that they are also going black for a moment, then come back.

Additional information:

I noticed that the flickering problem occurs only to those monitors that are 2nd or 3rd in the chain. Scenarios:

  1. Laptop -> Display_1 (not flickering) -> Display_2 (flickering) -> Display_3 (flickering)
  2. Laptop -> Display_1 (disabled from UI) -> Display_2 (flickering) -> Display_3 (disabled from UI)
  3. Laptop -> Display_1 (disabled from UI) -> Display_2 (disabled from UI) -> Display_3 (flickering)

Machine specs:

  • Intel Core i7-6600U
  • Intel HD Graphics 520 (Skylake GT2)
  • Ubuntu 17.10
  • GNOME 3.26.2

uname response:

xxx@xxx:~$ uname
Linux
xxx@xxx:~$ uname -r
4.13.0-37-generic

lspci response:

xxx@xxx:~$ lspci -nnk
00:00.0 Host bridge [0600]: Intel Corporation Skylake Host Bridge/DRAM Registers [8086:1904] (rev 08)
    Subsystem: Lenovo Skylake Host Bridge/DRAM Registers [17aa:2238]
    Kernel driver in use: skl_uncore
00:02.0 VGA compatible controller [0300]: Intel Corporation HD Graphics 520 [8086:1916] (rev 07)
    Subsystem: Lenovo HD Graphics 520 [17aa:2238]
    Kernel driver in use: i915
    Kernel modules: i915
00:08.0 System peripheral [0880]: Intel Corporation Skylake Gaussian Mixture Model [8086:1911]
    Subsystem: Lenovo Skylake Gaussian Mixture Model [17aa:2238]
00:13.0 Non-VGA unclassified device [0000]: Intel Corporation Device [8086:9d35] (rev 21)
    Subsystem: Lenovo Device [17aa:2238]
    Kernel driver in use: intel_ish_ipc
    Kernel modules: intel_ish_ipc
00:14.0 USB controller [0c03]: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller [8086:9d2f] (rev 21)
    Subsystem: Lenovo Sunrise Point-LP USB 3.0 xHCI Controller [17aa:2238]
    Kernel driver in use: xhci_hcd
00:14.2 Signal processing controller [1180]: Intel Corporation Sunrise Point-LP Thermal subsystem [8086:9d31] (rev 21)
    Subsystem: Lenovo Sunrise Point-LP Thermal subsystem [17aa:2238]
    Kernel driver in use: intel_pch_thermal
    Kernel modules: intel_pch_thermal
00:16.0 Communication controller [0780]: Intel Corporation Sunrise Point-LP CSME HECI #1 [8086:9d3a] (rev 21)
    Subsystem: Lenovo Sunrise Point-LP CSME HECI [17aa:2238]
    Kernel driver in use: mei_me
    Kernel modules: mei_me
00:17.0 SATA controller [0106]: Intel Corporation Sunrise Point-LP SATA Controller [AHCI mode] [8086:9d03] (rev 21)
    Subsystem: Lenovo Sunrise Point-LP SATA Controller [AHCI mode] [17aa:2238]
    Kernel driver in use: ahci
    Kernel modules: ahci
00:1c.0 PCI bridge [0604]: Intel Corporation Sunrise Point-LP PCI Express Root Port [8086:9d10] (rev f1)
    Kernel driver in use: pcieport
    Kernel modules: shpchp
00:1c.2 PCI bridge [0604]: Intel Corporation Sunrise Point-LP PCI Express Root Port [8086:9d12] (rev f1)
    Kernel driver in use: pcieport
    Kernel modules: shpchp
00:1f.0 ISA bridge [0601]: Intel Corporation Sunrise Point-LP LPC Controller [8086:9d48] (rev 21)
    Subsystem: Lenovo Sunrise Point-LP LPC Controller [17aa:2238]
00:1f.2 Memory controller [0580]: Intel Corporation Sunrise Point-LP PMC [8086:9d21] (rev 21)
    Subsystem: Lenovo Sunrise Point-LP PMC [17aa:2238]
    Kernel driver in use: intel_pmc_core
00:1f.3 Audio device [0403]: Intel Corporation Sunrise Point-LP HD Audio [8086:9d70] (rev 21)
    Subsystem: Lenovo Sunrise Point-LP HD Audio [17aa:2238]
    Kernel driver in use: snd_hda_intel
    Kernel modules: snd_hda_intel, snd_soc_skl
00:1f.4 SMBus [0c05]: Intel Corporation Sunrise Point-LP SMBus [8086:9d23] (rev 21)
    Subsystem: Lenovo Sunrise Point-LP SMBus [17aa:2238]
    Kernel modules: i2c_i801
00:1f.6 Ethernet controller [0200]: Intel Corporation Ethernet Connection I219-LM [8086:156f] (rev 21)
    Subsystem: Lenovo Ethernet Connection I219-LM [17aa:2233]
    Kernel driver in use: e1000e
    Kernel modules: e1000e
02:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS525A PCI Express Card Reader [10ec:525a] (rev 01)
    Subsystem: Lenovo RTS525A PCI Express Card Reader [17aa:2238]
    Kernel driver in use: rtsx_pci
    Kernel modules: rtsx_pci
04:00.0 Network controller [0280]: Intel Corporation Wireless 8260 [8086:24f3] (rev 3a)
    Subsystem: Intel Corporation Wireless 8260 [8086:0130]
    Kernel driver in use: iwlwifi
    Kernel modules: iwlwifi
Improve this question
1
  • Solution for problem 1 is to re-arrange displays while in display settings and having the built-in monitor enabled (do not Apply yet). After re-arrangement disable the built-in monitor and Apply the settings.
    – rkaalma
    Apr 18, 2018 at 13:34

1 Answer 1

Reset to default
2

I think I have found a solution to your problem 2:

Displays are flickering randomly (not a certain but all of the monitors, not at the same time tho). In addition to that they are also going black for a moment, then come back.

I have two (not three) U2414h monitors connected to my laptop (Dell XPS 13, Ubuntu 17.10) in a daisy-chain configuration. The monitor connected to the Laptop has DP 1.2 Enabled, the daisy-chained monitor has DP 1.2 Disabled.

According to xrandr the monitors support their native resolution at three refresh rates:

DP-1-1 connected 1920x1080+1920+0 (normal left inverted right x axis y axis) 527mm x 296mm
   1920x1080     60.00 +  50.00    59.94* 
DP-1-2 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 527mm x 296mm
   1920x1080     60.00 +  50.00    59.94*

If I operate both monitors at the refresh rate they announce as preferred (+), i.e., at 60.00 Hz, then I see the same symptoms as you: The outermost, daisy-chained monitor flickers occasionally (diagonal distortion, sub-second long blackouts).

If, however, I operate the monitors at 59.94 Hz, I don't see any issues on either monitor.

Improve this answer
2
  • Were you able to change refresh rate for all displays or only for the last display in the chain? With a setup like this: Laptop -[miniDP]-to-[DPin]-> Dell u2414h (DP1.2 enabled) -[DPout]-[DPin]-> Dell u2414h (DP1.2 enabled) -[DPout]-[DPin]-> Dell u2414h (DP1.2 disabled) I can't change the refresh rate first monitor in the chain. Also when I xrandr I get that the monitors are named as XWAYLAND3, XWAYLAND4 and XWAYLAND5.
    – rkaalma
    Apr 18, 2018 at 13:50
  • I was able to change the refresh rate for all of them (selected rate is marked with * in the above xrandr output). But I am using GNOME on X.org, whereas in your case Wayland might be involved. That being said, I am not sure whether changing the refresh rate is required for monitors (like the first) that don't flicker. I merely did this for the sake of uniformity and didn't experiment with mixed 59.94/50 Hz setups after the all-59.94-Hz setup worked for me.
    – Andreas Sewe
    Apr 19, 2018 at 14:29

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