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#1 2015-12-16 09:34:16

ob7
Member
Registered: 2015-08-17
Posts: 7

Having issues with a DisplayLink screen after pacman Syu

I'm running xmonad, xorg, and have an external monitor using a USB 2.0 DisplayLink. Everything was working fine until a Syu I had not ran in over a month.

The display link screen use to show up as DVI-0-1, but has been showing up as DVI-I-1 since the problem started.

The peculiar thing is I can get the screen to display, with a background and everything, but xmonad, xorg, or whatver is in charge doesn't really recognize it.  Xmonad keys do not do anything on the screen, it won't open up a console etc, in that screen, only on the main screen.  I can drag a window into the displaylink screen, and it appears fine.  But if I snap it back to grid it goes to the main screen.  Xmonad does not recognize it as another workspace, but when I hook up another screen not through the display link it works as expected, getting its own workspace in xmonad, and acting as its own seperate screen. 

But the screen hooked up via displaylink, it acts like its not there.  Its on, I can see the background, I can drag a window into it.  But it will not respond like a normal screen would.  I know my display link works as I plug it into an older running arch install and it still works on that.  Its only since I did a huge Syu that something went wrong.  I've tried downgrading xorg-devel, xmonad, xmonad-contrib, libdrm, lib32-drm, with no luck.  Dmesg output is normal when plugging the displaylink in.  Comparing it to older arch that runs it fine, the only difference I can see is when I run xmonad --listproviders, the old install shows
Provider 0 as
"Source Output, SInk Output"
and
Provider 1 (the displaylink) as
Sink Output

but the new install shows both as
Source Output, Sink Output


Any guideance and getting it to work again would be awesome.  I've been troubleshooting this for hours.  Was suppose to get some programming done for boss, but got side tracked with this.  If you need output of any commands or logs to help with this just let me know.


Thanks,
David

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#2 2015-12-18 01:53:34

ob7
Member
Registered: 2015-08-17
Posts: 7

Re: Having issues with a DisplayLink screen after pacman Syu

For the love of God, someone make a suggestion on how to fix my life, I mean my screen!  Its impossible for me to get anything done on less than four monitors!  Luckily my G750 supports 2 out the box, for a total of 3 screens, but to get four screens on my laptop my displaylink has to work....

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#3 2015-12-19 08:11:46

ob7
Member
Registered: 2015-08-17
Posts: 7

Re: Having issues with a DisplayLink screen after pacman Syu

Ok fam, I got this one covered.  8 hours of due diligence and my display link is back up and working.  This issue was not confined to only my laptop, when I did an Syu on a different laptop (which ran the display link prior) it also had same exact problems.
Both systems had upgraded xorg-server to 1.18 from 1.17.? ....
I don't know if it was xorg-server that broke the displaylink, or if it was the xf86-video-intel driver that broke the displaylink.

What I ended up doing is downgrading xorg-server to the prior version, its dependencies, and installing xf86-video-intel 1:2.99.917+381
I first fixed this on the second laptop that it broke on when doing the Syu, that way if I seriously jacked anything up my main system was still ok.
What I found was that after downgrading the xorg-server, my main graphics card no longer loaded the intel driver, so I couldn't hot plug the displaylink to provider 0, as both where using modesetting.
So I installed the intel driver over again that was compatible with the xorg downgrade, and I'm back in business!

During this process I learned about useful tools in finding out what you jacked up:
lsmod
lsusb
usb-devices
lspci | grep -e VGA -e 3D
cat /var/log/Xorg logs
cat /var/log/pacman log
dmesg sorta came in handy
diligence (only runs on humans)
and the AUR package called downgrade (I tried the one called downgrader but I ended up being successfuly using downgrade)

It was a lot of guess work, trying one thing, then another.  Having two computers that it worked on prior to an Syu really helped me figure out what went wrong.  When it broke on the second computer too, then I knew it was the upgrade that made the displaylink stop working.  I thought maybe it was my display manager, since both run xmonad, but even when disabling my .xinitrc to load the default window manager, the displaylink monitor was all jacked up.

I tried disabling all kinds of different modules.  I read the displaylink archwiki atleast 10 times.  I tried everything I could think of.  I was about to set up my desktops with xinerema to see if it could fix it, then I decided not too, that didn't make much sense.

Learning how to downgrade packages was a task in itself, although thanks to the wiki I now know how to go about that as well.

Heres the lesson to learn from this, if something breaks after an Syu, start by figuring out what packages the thing that broke was using, check the pacman log, try to downgrade whatever you think it may have been.

One thing I suggest to someone doing a full Syu after some time:  Copy your current pacman cache (which hopefully has all your current stable packages in) into a new folder, so when you download all the new packages you can go back to your backup and install those.  Of course its not completely necessary thanks to tools like "downgrade".

FYI, the display link shows up as DVI-0-1 again instead of DVI-I-1..  Not sure if this can help us narrow down what exactly went wrong.  But the displaylink is working again and its listed as DVI-0-1.

Thanks,
David

Last edited by ob7 (2015-12-19 08:12:47)

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#4 2016-02-08 09:32:52

poiu_ytrewq
Member
Registered: 2012-06-10
Posts: 10

Re: Having issues with a DisplayLink screen after pacman Syu

I have the same problem as you. Although I started with a whole fresh new system. Any ideas which packages I need to downgrade and the commands for them?
It's such a specific problem that I am glad somebody has it too.

Thanks in advance.

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#5 2016-02-08 17:55:27

ob7
Member
Registered: 2015-08-17
Posts: 7

Re: Having issues with a DisplayLink screen after pacman Syu

I believe its one of the XORG drivers.  Even though I got it working, it would randomly crash.  It caused me enough grief that I decided I didn't need a fourth monitor, so I'm back to three, and no display link.

But I would start with xorg-server.   The package worked flawlessly before the upgrade.  The version it was last working in on my setup was xorg-server 1.17, it broke when I upgraded to 1.18.

Last edited by ob7 (2016-02-08 17:56:31)

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#6 2017-02-11 10:42:14

fethio
Member
Registered: 2013-05-13
Posts: 12

Re: Having issues with a DisplayLink screen after pacman Syu

I was having similar problems after system update (linux 4.8.X->4.9.X and xorg-server 1.18->1.19)

I figured the evdi was updated (1.2.64-2 -> 1.2.64-3)  First, I updated evdi.

Then I reloaded xorg-video-intel (this package was removed somewhere during the pacman updates)  This causes the laptop monitor to be marked as Intel as opposed to modesetting.

This way, I got  displaylink to work!

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