Does Slackware support USB VGA?

mfoley · 01-19-2017, 06:39 PM

I'm looking to add a 3rd (and possibly 4th) monitor to my laptop. I currently have this running under Windows, but when booted to Slackware it doesn't see the USB VGA.

This site says the DisplayLink brand will work http://unix.stackexchange.com/questi...o-vga-on-linux, and the DisplayLink site http://www.displaylink.com/downloads advertises a driver for ubuntu.

I have two USB/VGAs that identify themselves as Magic Control Technology (in `lsusb`):

idVendor 0x0711 Magic Control Technology Corp.
idProduct 0x5100 Magic Control Technology Corp. (USB2VGA dongle)

The case of one is labeled "SIIG USB 2.0 to VGA" and the other is labeled "J5 Create". Both return the same product ID in lsusb so I'm guessing that these vendors both use the MCT chipset.

Has anyone done this?

Drakeo · 01-19-2017, 10:14 PM

question should read does the linux kernel support vga through USB if it does then up to you to read about Dongle and slackware

mfoley · 01-20-2017, 12:20 AM

Not sure I quite understand your comment. I can't really rephrase the question at this point. Do *you* know whether the linux kernel supports vga through USB? Since it appears that DisplayLink offers such a driver for Ubuntu (probably portable to Slackware), I would have to guess the answer is "yes" -- that is, if it *needs* to have kernel support. There might be other possibilities, but I'm not experienced enough with this to know.

When you say, "up to you to read about Dongle and slackware", are you referring to some article or resource you know about? If so, please share. I searched for "Dongle and slackware" and turned up plenty on WiFi and bluetooth, but nothing on VGA.

My objective is not to do any kernel programming or configuring Xorg or framebuffers -- I'm not proficient at that level. I'm asking whether anyone has done this with Slackware and, if so, what hardware, drivers, etc. they may have used. I'm interested in a solution where I can plug in the dongle, possible load driver(s), and possible modify config files. I'm not looking to *create* anything new.

rokytnji · 01-20-2017, 06:12 AM

Might help or not.

Local Search results

mfoley · 01-20-2017, 12:08 PM

More info ... in going to that http://www.displaylink.com/ site and examining the images of their products more carefully, I found that my SIIG USBVGA dongle was a dead-ringer for DisplayLink's UVGA-A8201, http://www.mct.com.tw/index.php?_Pag...pid=29&_lang=E, right down to the venti-ports on the side. My j5Create dongle looks very much like their UDVI-A8203, http://www.mct.com.tw/index.php?_Pag...pid=31&_lang=E. So, my hope is that my dongles are just re-labeled DisplayLinks. To that end, I downloaded their Ubuntu driver. And, googling for "Slackware DisplayLink Driver", I found this link: http://docs.slackware.com/howtos:hardware:displaylink.

Following the instructions there, I installed the dkms SBo package which is described as "Helper script for creating kernel modules.", then installed the DisplayLink driver. Output from that build is:

Code:

Verifying archive integrity... All good.
Uncompressing DisplayLink Linux Driver 1.2.65  100%  
DisplayLink Linux Software 1.2.65 install script called: install
/sbin/init: invalid option -- '-'
Usage: init {-e VAR[=VAL] | [-t SECONDS] {0|1|2|3|4|5|6|S|s|Q|q|A|a|B|b|C|c|U|u}}
which: no lsb_release in (/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin:/user/util/bin:/usr/lib/java/bin:/usr/lib64/kde4/libexec:/usr/lib64/libreoffice/program:/usr/lib64/qt/bin:/usr/share/texmf/bin)
WARNING: This is not an officially supported distribution.
Please use DisplayLink Forum for getting help if you find issues.
Installing
Configuring EVDI DKMS module
Registering EVDI kernel module with DKMS
warning: Generating 12 missing index(es), please wait...
Building EVDI kernel module with DKMS
Installing EVDI kernel module to kernel tree
EVDI kernel module built successfully
./displaylink-installer.sh: line 255: lsb_release: command not found
Installing x64-ubuntu-1604/DisplayLinkManager
Installing libraries
Installing firmware packages
Installing license file
Adding udev rule for DisplayLink DL-3xxx/5xxx devices
./displaylink-installer.sh: line 114: /lib/systemd/system/dlm.service: No such file or directory
chmod: cannot access '/lib/systemd/system/dlm.service': No such file or directory
ln: failed to create symbolic link '/lib/systemd/system-sleep/displaylink.sh': No such file or directory

I don't think I'm too concerned with the systemd stuff not being found as Slackware doesn't use systemd. The howto link gives instructions on manually starting this. I followed the post build instruction:

Code:

$ modprobe evdi
$ cd /usr/lib/displaylink
$ ./DisplayLinkManager &    # mine was actually in opt/displaylink/DisplayLinkManager

So far, all that seemed to work OK. `lsmod` shows the evdi module. Next I'm supposed to run `xrandr --listproviders` to show the new displays, and here's where I've ground to a halt:

Code:

xrandr --listproviders
No protocol specified
Can't open display :0

I've tried several things I've found by searching (permissions ...), but nothing is working. This should work even without the DisplayLink mucking about, right? Can anyone advise on how to fix this? I've also tried `xrandr --q1 --listproviders`, `xrand --q12 --listproviders` and just `xrandr`. All return the same error.

Can someone help me along?

mfoley · 01-20-2017, 12:24 PM

more info ... I had tried that `xrandr` command logged in as a normal user, with su - to root. For the heck of it, I tried logging in as root. That did work. However, no additional providers were listed:

Code:

# xrandr --listproviders
Providers: number : 1
Provider 0: id: 0x54 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 2 outputs: 3 associated providers: 0 name:AMD Radeon HD 6300 Series Graphics @ pci:0000:00:01.0

So, back to the drawing board on this

One additional thought, the howto instructions say they are for USB 3.0. I'm using USB 2.0. The howto link says

Code:

For devices and docks using USB 2.0, the built-in udl module should be sufficient to enable external monitors.

Could this possibly be my problem? Does anyone know what "the built-in udl module should be sufficient ..." means?

mfoley · 01-28-2017, 08:16 PM

Next I'm trying the MTC driver. I'll revisit this thread if I can find a DisplayLink device. I'm going to post a new thread for MTC.

mfoley · 02-02-2017, 02:00 AM

I'm back to this thread. I could not get anything going with the MTC driver. I did purchase a DisplayLink USB 2.0 VGA adapter. Some progress. I followed the instructions here: http://docs.slackware.com/howtos:hardware:displaylink, even using the same DisplayLink driver version as the author used (the more recent drivers gave errors when running the DisplayLinkManager program, and they all expected systemd). My output for installing is exactly like that on the webpage:

Code:

$ ./displaylink-driver-1.0.335.run
Verifying archive integrity... All good.
Uncompressing DisplayLink Linux Driver 1.0.335  100%  
DisplayLink Linux Software 1.0.335 install script called: install
Distribution discovered: "NAME=Slackware"
WARNING: Kernel version 4.4.38 is not supported. Highest supported version is 3.19.
Installing
Configuring EVDI DKMS module
Registering EVDI kernel module with DKMS
Building EVDI kernel module with DKMS
Installing EVDI kernel module to kernel tree
EVDI kernel module built successfully
Installing x64/DisplayLinkManager
Installing libraries
Installing firmware packages
Installing license file
Adding udev rule for DisplayLink DL-3xxx/5xxx devices

except I didn't get an "Unknown distribution" warning. I then started the driver per the instructions:

Code:

# modprobe evdi
# cd /usr/lib/displaylink
# ./DisplayLinkManager &

then ran the `$ xrandr --listproviders` command, and this time, finally it saw the 2nd display!

Code:

$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x54 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 2 outputs: 3 associated providers: 0 name:AMD Radeon HD 6300 Series Graphics @ pci:0000:00:01.0
Provider 1: id: 0x527 cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting
Provider 2: id: 0x41 cap: 0x3, Source Output, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting

I then ran the final xrandr command:

Code:

# xrandr --setprovideroutputsource 2 0

# xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x54 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 2 outputs: 3 associated providers: 1 name:AMD Radeon HD 6300 Series Graphics @ pci:0000:00:01.0
Provider 1: id: 0x41 cap: 0x3, Source Output, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting
Provider 2: id: 0x527 cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 0 name:modesetting

Not sure why I show 3 providers or what the --setprovideroutputsource actually does.

When I go to KDE Launcer > System Settings > Display Configurations, it does show the new monitor, sort of, but its grayed out.

Making progress, but I need some suggestions on what to try next.

Later ...

Actually, the display did finally show in KDE - first I got a "do you want to configure ..." dialog. I answered to "try automatically" whereupon I got a screen of 4 alternating green and purple horizontal stripes. Doing a manual config doesn't seem to help.

Ideas?