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What is Displaylink?
Displaylink is a company who make USB-Video adapter chips.
These chips are used in devices that allow you to connect extra monitors into your computer via USB. The idea is that a simple plug and play device allows you to hook up multiple screens.
Displaylink Devices using Displaylink Chipsets
- USB2 or USB3 to DVI, HDMI or VGA adapters
- USB Docking stations and powered USB hubs including a Displaylink graphics output port
- USB powered LCD/LED monitors, possibly with touchscreen
- Portable USB powered monitors (screens)
Are there any decent working Displaylink drivers in existence?
Displaylink have created drivers for Windows XP, Windows 7/8 and Mac OSX.
The Windows XP driver allows you to tilt Displaylink monitors and the software will automatically rotate your display. Very cool.
Neither the Windows 7 software nor the Mac drivers support the automatic tilt/rotate functionality that is advertised.
As a Displaylink customer I get this really horrible feeling that Displaylink doesn’t care about me, and does not care that I spent my money on their product and that I can’t even use it.
Displaylink firmware updates
Displaylink has a very foolish policy of treating their customers like idiots.
Displaylink drivers will automatically update the firmware on your device as soon as you plug it in. (according to the readme files bundled with their drivers)
This is done completely without asking your permission, without any warning that it will happen and without any kind of status display to actually let customers know that a firmware update is in progress.
It should come as no surprise that Displaylink also do not provide any method to roll back the firmware to a previous version.
Whats wrong with invisible firmware updates?
Many problems can arise from firmware updates.
- If firmware updates happen invisibly to customers, their products can suddenly and silently brick themselves or become unstable, leaving the the customer stranded without any clue about the cause of the problem.
- Many computer’s USB ports don’t have enough power to power USB-powered displaylink monitors properly, and so they flicker and the power fluctuates. Thats not a good environment for updating firmware.
- If you don’t know the firmware is being updated, you might unplug, shutdown or your battery might die halfway through flashing the EEPROM, resulting in a bricked displaylink device.
- Displaylink devices like DL-165 can work for many months Linux with the open source driver, in a frustrating/glitchy but sort of working manner, then you connect them to a windows machine, then plug back into a linux machine and suddenly it doesn’t work anymore.
Basically if you’ve got a displaylink device that functions on a linux open source driver, you can’t trust their Windows/Linux blob drivers (even just for a quick test) because they might get their firmware updated and stop functioning on the open source drivers.
Displaylink Linux non-Support
Displaylink does not provide any working linux drivers.
Displaylink’s lies and deception
Displaylink want it to look like they care about the linux community.
It should be fairly obvious they don’t since they haven’t bothered to make a linux driver
But the problem is a little worse than that.
Look at the displaylink’s joke about supporting linux. They offer a link to a page containing outdated and useless information. Those links refer to software that is years out of date. It is a complete joke. Offensive really.
Please note, that is the community’s efforts and work on that page, not Displaylink.
Also note how much they have struggled to get anything working.
If you find half of those links working I’ll be impressed, that site is so dead.
* Some people have had success using Displayink adapters on Linux despite Displaylink’s efforts to conceal their products mechanisms.
If you look at the website of this linux hobbyist who is at the forefront of hacking displaylink products…
Yes I said ‘hacking’.
Thats what you have to do when Displaylink actively tries to prevent everyone from figuring out how their products work. You’ll find some very interesting comments.
Well, so DisplayLink released their own LGPL library, half a year after we figured all this stuff out. Nice. But wait, let’s have a look at this library. Hmm, the compression is missing. So it’s pretty useless compared to the closed-source drivers – it looks like it’s targeted mainly for embedded stuff like LCD advertising signs and so on. Moreover, the init sequences are still encrypted – come on, what’s the point? I’ll decrypt them next week and put them in the Wiki.
You see by the time Displaylink released their joke of an open source linux driver to the Linux community.
The linux community had already spent many hours hacking and reverse engineering Displaylink products to try get them working and had progressed further than the functionality provided by Displaylink’s “open source driver” which still contains encrypted blobs of data and is missing compression, which means performance is very poor.
There is still a lot of information missing about how to get Displaylink display adapters working properly on linux.
Displaylink’s other joke is their token Open Source Software Forum
The truth is Displaylink are actively trying to stop people from understanding how their software works, by encrypting it, even in their fake ‘open source’ contribution.
Displaylink is self destructive and counter-productive
If you see the above quote, this hacker laughs at Displaylink’s encryption attempts, yet he says he doesn’t have time to work out all the compression bugs right now.
With so much progress made into cracking Displaylink’s encryption protocol and compression by one hobbyist hacker, its obvious that a company with any commercial interest will have no problem hacking and ripping off Displaylink’s design. All a competitor needs is one person dedicated to hacking the device and they will probably figure everything out within a matter of days.
So the only thing Displaylink has been successful in is pissing off their customers who use linux.
Why is it so time consuming to hack Displaylink products?
Well as you’ll see from the video, Displaylink have obfuscated and encrypted their protocol.
Yes all the communication between the PC and the displaylink USB adapter is encrypted. What a waste of CPU power and battery life! All because of Displaylink’s paranoia. This effort to encrypt the data was a waste of time however, as you’ll see from the video and the other link above. These linux enthusiasts have had no trouble defeating Displaylink’s encryption.
Probably the main reason Displaylink is so paranoid about their design is they believe their compression technology is really special, allowing for high resolution video to be streamed to the displaylink device over relatively low bandwidth USB2 connections. (+-29MB/s).
But how special can their technology really be? There are so many video compression technologies around these days. Delta frames and image compression are nothing new.
Which Linux distro has the best support for Displaylink?
- The new Linux kernel (apparently after 3.4 or 3.5) some experimental Displaylink driver is built in. (the current version of the linux kernel is 3.8)
- Ubuntu 13.04 seems to be completely unaware of some displaylink monitors.
- Fedora 19 seems to have better detection but still shows corrupted images and crashes. Your success will depend on what Displaylink chipset you try.
Displaylink violated the GPL
Displaylink could be taken to court over their GPL violation. They included libusb as part of their own product, which they have been selling for a profit.
Due to their GPL violation Displaylink may be required to release their source code, thus solving the “Displaylink Linux driver problem”.
In light of this, it is ironic that Displaylink are so paranoid about their software being stolen and used without giving them any credit. (to the extent that they deny their customers the ability to use their products)
Displaylink are NOT ‘open source friendly’
Displaylink claim to be open source friendly, but in reality they are totally the opposite.
- Displaylink’s so-called “open source contribution” is of no significant value.
Hackers had already figured out everything they provided.
Displaylink’s “open source release” was really an exploitation of the work of open source hackers, a PR stunt.
- Displaylink actively try to prevent developers from finding out how their products function by encrypting and obfuscating their software, delaying open source drivers from being developed.
- Displaylink have exploited the open source libusb, for their own profit, without paying any royalties or giving credit to the original open source authors.
Displaylink have violated the General Public License agreement with which libusb was shared.
What Displaylink should do
- Create an open source linux driver, with compression and auto-rotation support and without encryption (lets not waste CPU on something so useless)
- Release full specifications of how their hardware works so that the linux community can make a decent working driver.
- Stop being so afraid someone’s going to take your intellectual property and magically start a business to compete with you. A USB-display-bridge is not exactly rocket science, any chinese hardware engineer can cobble something together quickly that will work well enough at least for office work. #paranoid. This just frustrates the open source community who could be your happy customers, and support you via recommendations building products using your products and improving your (future) open source drivers for you.
What we can do (that means you also)
Lets clear up these misconceptions that Displaylink have successfully created:
- Displaylink cares about open source
- Displaylink are trying to make a Linux driver but they find it hard
- Its okay to be without a Linux driver or multi-monitor support on Linux
- We have waited a few years already, so we can wait a few more years
- Linux users don’t matter
People need to know the truth about Displaylink and companies like Displaylink.
Displaylink perpetuate the chicken and egg problem.
Linux adoption has been low in the past because of lack of drivers and being un-userfriendly.
Things have changed.
Linux is more user-friendly than ever and the average user has no problems with drivers.
By the way when I say Linux, I’m loosely referring to GNU/Linux.
Linux is the really just the kernel, and GNU is all the free software that combined with the kernel make up the OS that we use.
So GNU/Linux is the combination of the two. Most people mean GNU/Linux when they refer to Linux. (whether they know it or not)
- Linux is the fastest growing OS in the world, growing by 64% per year.
- Ubuntu’s hardware partners estimate Ubuntu will be pre-installed on 10% of PCs sold in 2014!
- The best developers are using Linux
- Mac OSX is based on BSD (aka Berkerley Unix) Linix is an independent free Unix-like OS. I believe recent success of OSX is both their appeal to novice users as well as people who want a well polished and packaged product AND semi-technical users who have the ability to get Linux software running on Mac relatively easily. Of course there are downsides to using Apple products, such as giving up freedom of choice, privacy, control and accepting higher purchase costs, maintenance costs and vendor lockin.
As long as Apple are able to deliver reasonably good quality hardware, simplifying customer’s hardware and software choices (making choices for them), Apple will be successful. From a purely software perspective, as Linux’s usability continues to improve, Linux will continue to absorb users from both Apple and Microsoft. Until Ubuntu or some other company starts producing laptops where the hardware is married to the software in a friendly package (as with Apple and their products, or Android with Android devices) then we will see a massive growth in Linux as a Desktop OS.
- Android, the fastest growing and most popular mobile OS is based on Linux
- Most recent software innovation is coming out of Linux.
- Linux/UNIX runs most servers and almost all networking hardware (routers) (even M$ use it in their data-centers).
- Wikipedia’s success is a testament to freedom and collaboration.
- Companies like Google who embrace open source have had immense success.
Linux will become the most popular OS. It is just a matter of time.
We are living in a time of freedom of information and choice. Old patterns (in every area of life) that are characterized by fear and deceit are falling away. As we educate ourselves we make wiser choices that everyone benefits from. Instead of grasping withholding we find that openness, sharing and honesty leads to collaboration and collective prosperity.
Let’s do our part for the whole, let the truth be known, collectively taking part in our technological evolution.
It is happening anyway, it is inevitable, the sooner we all participate and contribute, the sooner we all benefit.
Finally, when Displaylink realizes that its better to play nice than hide, reward them and welcome them.
- Table of other posts about other linux users experiences trying to use displaylink products on linux, whether they were successful, how out of date the information is and how complicated their method was.
- Some links that might help people get Displaylink adapters working on linux
- What do you think of Displaylink’s linux policy?
- Suggest alternative USB-DVI chipset manufacturers that support linux
- Let me know if you have any useful info for getting Displaylink adapters working easily
- If you’re using a Displaylink device, please let me know if you got it working on linux or not including model #, distro & version
This post has been online for a good while. Last update was almost 4 years ago.
Displaylink created Extensible Virtual Display Interface (EVDI)
This looks like their first genuine open source contribution. Definitely a positive beginning (let’s hope): https://github.com/DisplayLink
It Looks like a nice concept. However don’t get too excited. Their description says you must use it with their closed-source binary blob driver
Displaylink created a linux driver!
But don’t celebrate just yet.
Yep, it’s a closed source binary blob.
Binary blob drivers suck
Yeah, using a binary blob driver is like inviting a known rapist for a sleepover. Okay maybe not a known rapist. Maybe just someone under a bridge who looks kind of dodgey.
If you’re wondering what’s wrong with a closed source binary blob driver, read the wikipedia article or school yourself on 101 in Open Source Philosophy or Security. https://en.wikipedia.org/wiki/Binary_blob#Problems
The most important part is this: In 2008, 176 Linux kernel developers signed a Position Statement on Linux Kernel Modules that stated “We, the undersigned Linux kernel developers, consider any closed-source Linux kernel module or driver to be harmful and undesirable… We have repeatedly found them to be detrimental to Linux users, businesses, and the greater Linux ecosystem.
In a nutshell if you start introducing closed source binary blob drivers into your system, you’re potentially opening up horrific backdoors. That means random attackers on the internet can gain root access to your computer. Your encryption keys, your private data, passwords, banking information etc, etc.
Nvidia closed source binary blob driver proven to provide hackers easy root access to your computer
There was a security vulnerability present in ALL Nvidia Linux closed source binary blobs whereby unprivledged attackers could gain root access. The vulnerability was reported to Nvidia but they were very slow to respond with a fix https://askubuntu.com/questions/171230/nvidia-linux-driver-hack-gives-you-root-access.
The open source Nvidia linux driver did not possess the vulnerability.
Developing the open source Nvidia driver has been made unnecessarily difficult by Nvidia not releasing hardware information and specs necessary for an opwn source driver to be developed. It has only happened after a massive amount of effort and reverse engineering Nvidia’s closed source binary blobs.
I’ve got a great idea. Let’s give a closed source binary blob from DisplayLink root access to our computers. With no ability to verify that there are no security vulnerabilities or backdoors. Yeah, I’m so excited about doing that… racing for their website to find the download page. With closed eyes I kneel before thee. Root my computer please! And do with it whatever you like. Don’t show or tell. Thanks so much!!!
As a final note about Nvidia. Some inspiring words from our Linux leader: https://www.youtube.com/watch?v=_36yNWw_07g
There may be some value in Displaylink’s new blob driver
The Ubuntu DisplayLink driver could be run inside a disposable Linux VM inside Virtualbox
If anyone knows how to jail DisplayLink’s driver, let’s hear about it in the comments 🙂