New issue
Advanced search Search tips
Note: Color blocks (like or ) mean that a user may not be available. Tooltip shows the reason.
Starred by 71 users

Issue metadata

Status: Verified
Closed: Mar 2016
EstimatedDays: ----
NextAction: ----
OS: Chrome
Pri: 2
Type: Feature

  • Only users with EditIssue permission may comment.

Sign in to add a comment

Support UDL 3.0 on ChromeOS

Project Member Reported by, Dec 28 2015

Issue description

I'm not aware of an existing bug filed specifically for UDL 3.0 so filing a new one with RVG.

Currently Chrome OS supports UDL 2.0 only. UDL 3.0 is a completely different protocol and is not backwards compatible.

See also  bug 379448  "USB Monitor with Chromebook". Multiple different issues are being discussed there.  Bug 448143  covers support for >= 3 monitors, but I suspect that some users are in fact trying to use UDL 3.0 monitors.

Today when a UDL 3.0 device is plugged in, it is ignored at the kernel level. That is, no DRM UDL device is registered upon USB hot plug.

For comparison here's the lsusb printout of a UDL 2.0 device vs. a UDL 3.0 device.
21.5 KB View Download
2.7 KB View Download

Comment 1 by, Dec 29 2015

CC jdufault as this may be related to  bug 379448 

According to Asus ( MB168B is powered by a "USB 3.0 cable" however it also mentioned that the device is "backwards compatible with USB 2.0 port". It's not clear at all whether that means the device supports UDL 2.0 or not.
MB168B works with USB 2.0, but it uses the DL3 protocol, which we don't support. As a rule of thumb, if something works with USB 3.0 (even if it's compatible with USB 2.0), then it uses DL3.
Does this need to stay RVG?
Yes, otherwise we'll get tons of users making noise.
"Users making noise" is generally not a reason to keep a bug restricted. We can disable comments if you're concerned about that.

Comment 6 by, Dec 29 2015

We don't really have any documentation on the DL3 protocol (although DisplayLink provides proprietary / binary drivers).

We could add bInterfaceProtocol = 0x03 to the USB device ID table in udl_drv.c so that kernel would recognize DL3 devices but then we're stuck because the DL2 driver fails to retrieve EDID.

Comment 7 by, Dec 29 2015

P.S. on #6: by "proprietary / binary driver" I meant a Windows-only SETUP.EXE file. Their license explicitly prohibits reverse-engineering.

Comment 8 by, Dec 29 2015

Digging further in my inbox it looks like DisplayLink did make a Linux binary driver available in July (1.0.68 was the latest version).
There are 3 components we'll need to integrate:

- The kernel module which we'll need to land in our kernels. We should start there I think.

- The binary daemon. We have creased the chromeos/partner_private/dlm/ repo for it. We should be able to put the (closed source) source there and build it for x86 & arm.

- Finally there is a user space library which is open source which we are going to need an ebuild for.
Status: Assigned
Labels: Cr-Enterprise
Labels: -Restrict-View-Google Restrict-AddIssueComment-EditIssue
Marking this publicly readable w/o comments, per #3,4,5.
 Issue 577806  has been merged into this issue.
 Issue 379448  has been merged into this issue.

Comment 18 by, Feb 23 2016

Tested Dell DisplayLink 3.0 D3100 dock with Dell Chromebook 13

Tested on 48.0.2564.92, and the displays attached to the dock via HDMI did not receive any signal.
Dell displaylink D3100 debug-logs_20160211-131537.tgz
532 KB Download

Comment 19 by, Feb 23 2016

re:#18 please refer to comment #9. There are still many pieces missing before we can get UDL 3.0 functional on Chrome OS. The kernel patches and ebuilds haven't even landed on TOT yet. So for now there is no point "testing" UDL 3.0 because it won't work.
Do we expect UDL 3.0 for USB 3 DisplayLink devices to be supported in the foreseeable future? 
It appears some vendors (e.g. Targus) are discontinuing USB 2.0 DisplayLink adapters.
Enterprise customers are looking to utilise multiple displays and reluctant to buy legacy hardware.
Labels: enterprise-hotlist
Pinging for an update on this one. Large APAC customer looking to utilize 3.0 Display docks. 
Status: Fixed (was: Assigned)
Labels: M-51
re #22: UDL 3.0 is coming to M-51, starting with Intel Broadwell boards.
Thanks Team - awesome news
Status: Verified (was: Fixed)
verified on Mimo UDL touch on Paine in ChromeOS 8172.25.0 / 51.0.2704.37
Status: Fixed (was: Verified)
@26: This is a DL 2.0 device, please re-test with a DL 3.0 device.
Status: Verified (was: Fixed)
Verified, thanks to hshi@'s Dell D1000 dock station. 

Sign in to add a comment