How to install DisplayLink USB to HDMI converter

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Omar Morando

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Feb 3, 2020, 4:33:29 AM2/3/20
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Hello,
I'm a Qubes user, I'm using version 4.0.1 on my Dell Inspiron 13 5378 with I-7, 16 GB of RAM, 2 TB SSD and everything works well.

I need to use a USB 3.0 HDMI converter for an external monitor, in addition to the HDMI port built into the laptop. I have read a couple of topics from Reddit about this RPM driver for Fedora but nobody has managed to make it work:
Do you have any suggestions? Do you know if someone has managed to install it or if there is a specific version for Qubes? Searching the net, I did not find any other information.
If you give me support I can do tests that can then be made public for other users.
Thank you


Omar Morando
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Matthias Horn

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Feb 4, 2020, 3:39:22 AM2/4/20
to Omar Morando, qubes...@googlegroups.com
hi,

I got this working on my laptop (dual 4K monitors), but It’s complicated, and compromised the security of dom0 (if that’s okay for you depends on your reasons for using Qubes)

I’ve sketched out the steps i took below, these intentionally are not step by step instructions. It’s fragile and you will probably have to do some debugging...

- ensure that the USB3 controller that you plug the display link adapter into is attached to Dom0 and not Sys-USB (I had to completely disable my sys-usb wich breaks other stuff).
    This opens up a huge attack surface on Dom0. Only do this if you trust all the USB devices you’ll be plugging in...


- I needed to rebuild and install the display link and evdi RPMs. I grabbed the latest src.rpm got each and then rpmbuild in Dom0 to get installable packages (installing all the build and install dependencies with Qubes-Dom0-update).

This is a terrible idea, I should have used mock in a domU to build the RPMs... it’s also not ideal to be installing an untrusted binary blob (display link) in dom0

- (probably related to driving 16billion pixels...) I regularly have to restart X before I can use the extra screens (stop all vms, remove the X shared memory file, restart X, setup the extra screens, start the VMs as needed)

It’s probably  possible to do this in a cleaner way, run display link in the sys-usb qube and share the EVDI virtual frame buffer devices between Dom0 and Sys-USB, but the later part is probably hard to get working reliably...

Hope this is helpful,

‘Tias
    

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On 3 Feb 2020, at 09:33, Omar Morando <omar.m...@hotmail.it> wrote:


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Omar Morando

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Feb 5, 2020, 11:00:15 AM2/5/20
to Matthias Horn, qubes...@googlegroups.com
Hi Matthis,
thanks a lot for your help.

Ok, I use Qubes for security reasons and I don't want to compromise the security of dom0, even if the second external monitor is important for working better.

I prefer to wait for a different solution, hoping that someone somewhere will be able to use displaylink while maintaining system security.

Thanks again, ciao

Omar Morando
On Feb 4 2020, at 9:39 am, Matthias Horn <matt...@gmail.com> wrote:
hi,

I got this working on my laptop (dual 4K monitors), but It’s complicated, and compromised the security of dom0 (if that’s okay for you depends on your reasons for using Qubes)

I’ve sketched out the steps i took below, these intentionally are not step by step instructions. It’s fragile and you will probably have to do some debugging...

- ensure that the USB3 controller that you plug the display link adapter into is attached to Dom0 and not Sys-USB (I had to completely disable my sys-usb wich breaks other stuff).
    This opens up a huge attack surface on Dom0. Only do this if you trust all the USB devices you’ll be plugging in...


- I needed to rebuild and install the display link and evdi RPMs. I grabbed the latest src.rpm got each and then rpmbuild in Dom0 to get installable packages (installing all the build and install dependencies with Qubes-Dom0-update).

This is a terrible idea, I should have used mock in a domU to build the RPMs... it’s also not ideal to be installing an untrusted binary blob (display link) in dom0

- (probably related to driving 16billion pixels...) I regularly have to restart X before I can use the extra screens (stop all vms, remove the X shared memory file, restart X, setup the extra screens, start the VMs as needed)

It’s probably  possible to do this in a cleaner way, run display link in the sys-usb qube and share the EVDI virtual frame buffer devices between Dom0 and Sys-USB, but the later part is probably hard to get working reliably...

Hope this is helpful,

‘Tias
    

Sent from my iPhone

On 3 Feb 2020, at 09:33, Omar Morando <omar.m...@hotmail.it> wrote:


Hello,
I'm a Qubes user, I'm using version 4.0.1 on my Dell Inspiron 13 5378 with I-7, 16 GB of RAM, 2 TB SSD and everything works well.

I need to use a USB 3.0 HDMI converter for an external monitor, in addition to the HDMI port built into the laptop. I have read a couple of topics from Reddit about this RPM driver for Fedora but nobody has managed to make it work:
Do you have any suggestions? Do you know if someone has managed to install it or if there is a specific version for Qubes? Searching the net, I did not find any other information.
If you give me support I can do tests that can then be made public for other users.
Thank you


Omar Morando

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