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-   -   High CPU load (D3100 Ubuntu 15.04) (https://displaylink.org/forum/showthread.php?t=64039)

godrica 08-24-2015 07:14 PM

High CPU load (D3100 Ubuntu 15.04)
Hi all...

I'm getting extremely high CPU load on my Dell XPS 13 machine running Ubuntu 15.04.


Is this behaviour normal?
What are your experiences with CPU load and Display link manager?

mlukaszek 08-26-2015 07:14 AM


This is not normal - can you create a coredump file from a running DisplayLink Manager (e.g. using gdb and its generate-core-file command)?


vkorecky 10-30-2015 12:19 PM

Ubuntu 14.04 - the same problem
I have the same problem on my Ubuntu 14.04

Ubuntu info:
Linux AcerV7 3.19.0-31-generic #36~14.04.1-Ubuntu SMP Thu Oct 8 10:21:08 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

DisplayLink device:
HP 3005pr

lspci output:
00:00.0 Host bridge: Intel Corporation Haswell-ULT DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 09)
00:03.0 Audio device: Intel Corporation Haswell-ULT HD Audio Controller (rev 09)
00:14.0 USB controller: Intel Corporation Lynx Point-LP USB xHCI HC (rev 04)
00:16.0 Communication controller: Intel Corporation Lynx Point-LP HECI #0 (rev 04)
00:1b.0 Audio device: Intel Corporation Lynx Point-LP HD Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation Lynx Point-LP PCI Express Root Port 1 (rev e4)
00:1c.2 PCI bridge: Intel Corporation Lynx Point-LP PCI Express Root Port 3 (rev e4)
00:1c.3 PCI bridge: Intel Corporation Lynx Point-LP PCI Express Root Port 4 (rev e4)
00:1c.4 PCI bridge: Intel Corporation Lynx Point-LP PCI Express Root Port 5 (rev e4)
00:1d.0 USB controller: Intel Corporation Lynx Point-LP USB EHCI #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation Lynx Point-LP LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation Lynx Point-LP SATA Controller 1 [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation Lynx Point-LP SMBus Controller (rev 04)
01:00.0 3D controller: NVIDIA Corporation GK107M [GeForce GT 750M] (rev ff)
04:00.0 Network controller: Intel Corporation Wireless 7260 (rev 73)
05:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. Device 5287 (rev 01)
05:00.1 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 14)

lsusb output:
Bus 003 Device 002: ID 8087:8000 Intel Corp.
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 003: ID 17e9:430a DisplayLink HP Port Replicator (Composite Device)
Bus 002 Device 002: ID 0451:8040 Texas Instruments, Inc.
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 007: ID 04f3:0086 Elan Microelectronics Corp.
Bus 001 Device 005: ID 8087:07dc Intel Corp.
Bus 001 Device 003: ID 04f2:b3d6 Chicony Electronics Co., Ltd
Bus 001 Device 010: ID 04b4:0060 Cypress Semiconductor Corp.
Bus 001 Device 009: ID 1bcf:05cf Sunplus Innovation Technology Inc. Micro keyboard & mouse receiver
Bus 001 Device 008: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 001 Device 006: ID 048d:1165 Integrated Technology Express, Inc. IT1165 Flash Controller
Bus 001 Device 004: ID 0424:2517 Standard Microsystems Corp. Hub
Bus 001 Device 002: ID 0451:8042 Texas Instruments, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

xenith 10-30-2015 04:10 PM

Ok speculation time -

I had this issue at one point in my initial purchasing of this hardware which was when I wrote this:


I had made the assumption that the CPU usage was otherwise normal (mine was a little lower but still _very_ high) for driving two screens.

For curious testing purposes I installed windows on a USB hard drive, booted that, and installed the proper displaylink drivers for windows 8.1 on that. Low and behold... It was capable of driving not two, but _3_ 1080p screens with zero lag over 1 USB3 port with relatively little CPU usage. This surprised me due to the poor performance I was seeing on Linux.

Point being, the hardware is capable. It's the failure of this company to produce Linux drivers that work as well that cause our pain and suffering.

Now, the reason that I'm writing this post -

Strangely, when I booted back into Fedora 22, I noticed that the lag wasn't present anymore (the screens no longer felt like they were clocked at 30Hz when they were previously) and the CPU usage was decreased dramatically.

I'm not sure whether or not I had a lingering kernel upgrade in between, but my speculation is that the windows drivers properly updated the firmware on the device itself, where the Linux drivers didn't. So, as a potential 'fix' attempt to find a windows computer that you can plug it into first.

Unfortunately, again, whether it's the latest kernel or the firmware that was upgraded on the device, I don't know. But there are a whole other host of issues that come from whatever upgrade happened, too. For some reason, unlike before, the devices fails ungracefully if X is ever restarted and gives the following error message until the computer is rebooted:

[ 453.842446] [drm:check_crtc_state [i915]] *ERROR* mismatch in ips_enabled (expected 1, found 0)
[ 453.842633] [drm:check_crtc_state [i915]] *ERROR* mismatch in ips_enabled (expected 1, found 0)

It's as if something isn't being released properly.

geekygator 04-08-2016 10:49 PM

I am having the same high CPU issue, Ubuntu 14.04, Dell XPS 13, D3100. CPU use hovers between 40% and 140% according to top.
I attempted to connect the device to a windows machine using the windows driver, but there was no improvement. Granted, I did not connect displays to the device when I connected it to Windows, nor reboot windows.

trofim 04-15-2016 10:08 AM

Same issue on ubuntu 15.10 with kernel 4.2.0-35-generic.

mlukaszek 04-15-2016 12:54 PM

Thanks for your reports.

Again, it would be useful if someone could attach a dump from DisplayLinkManager process so we can investigate - see my comment above.


R.E.L 05-07-2016 08:16 AM

Simmilary problem solved
Hi together,

I have an Ubuntu 14.04 trusty up to-date. An Year ago my DisplayLink was working with a lot of changes in the udev. Then I don't need the second display using DisplayLink. Now I have a need to use the second display. It now does not work.

So I investigate and found the new DisplayLink driver for Ubuntu and installed them. First it doesn't work because I had kernel 3.13.0-45. I Installed LTS wily kernel 4.2.0-35. After some display settings it works with a many crashes an always an poor performance. The mouse moves very slow and tipping an character takes seconds.

I take a deep look at it and found a solution:
  • sudo displaylink-installer uninstall
  • Remove my old DisplayLink udev entries
  • create a file /etc/modprobe.d/98_no_udl.conf with data: blacklist udl
  • reboot
  • run install
  • sudo ./displaylink-driver-1.0.335.run

Now the DisplayLink display and my primary display working without any problem.:)

Hope this helps You to regards Rainer

cpo 05-17-2016 01:46 PM

Same issue here. Please find the core dump from DisplayLinkManager. Uncompressed size is 2.4GB.


Additionally I'm getting logged off when I plug in the D3100 for the first time, I've two mouse cursors - one static and one which is flickering.

When the D3100 is attached during system startup, the secondary screen stays black and I've a couple of kernel stacktraces in the journal. Looks like these: https://github.com/DisplayLink/evdi/issues/28

mlukaszek 05-19-2016 10:16 AM

@cpo: Can you attach the output of the support tool, so we can know more details of your setup?

Edit: and it would also be great if you could attach an archive with all the libraries that DisplayLinkManager would link to at runtime (i.e. everything that you see mentioned in the output of ldd /usr/lib/displaylink/DisplayLinkManager), otherwise it would be hard to read anything from the dump without installing rawhide somewhere I guess.


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