On 24 March 2018 at 19:07, Russell <rreiter91@gmail.com> wrote:
On March 24, 2018 9:53:59 AM EDT, Russell Reiter <rreiter91@gmail.com> wrote:
On 23 March 2018 at 20:01, Scott Sullivan via talk <talk@gtalug.org> wrote:
On 2018-03-23 12:50 PM, Giles Orr via talk wrote:
A couple days ago I got a Best Buy flyer, and they have this item:
https://www.bestbuy.ca/en-ca/product/asus-zenscreen-15-6-fh d-60hz-5ms-gtg-ips-lcd-monitor-mb16ac-dark-grey/10737845.aspx
<https://www.bestbuy.ca/en-ca/product/asus-zenscreen-15-6-f hd-60hz-5ms-gtg-ips-lcd-monitor-mb16ac-dark-grey/10737845.aspx>?
It's a portable IPS LCD screen from Asus. I have a similar item
from
about three years ago that has two connectors, one for USB
the other for VGA/HDMI. There were other models at the time that used only one connector, USB for both data and power - but that required a driver (and would have been painfully slow if it was USB2).
But now here's this new model: it's one connector only, USB-C. And presumably USB3.1. And USB3.1 can carry video. But at this point I get lost among the standards and their implementations and which one supports what. I have an Asus Zenbook (it's Linux-only at this point) that has a USB-C connector, but I suspect it's USB3.0. So the first question is: how do I check that? Second, does Linux support video-over-USB3.1? Do I need a special cable? Is this "Thunderbolt?" How can I check if my machine would support this?
The Spec you linked say it's DisplayLink, which is the software
video solution that requires a driver.
https://en.wikipedia.org/wiki/DisplayLink
USB-C is only a specification for a cable and connector, and somewhat agnostic about the data communications spec used across it. The cables are of high enough quality that they can support multiple data communications specs, generally referred to as alt-modes.
https://en.wikipedia.org/wiki/USB-C#Alternate_Mode_partner_specifications
Thunderbolt 3 for example co-oped the USB-C cable spec for it's
cables,
much like in the previous generations it co-oped the mini-displayport cable spec.
Intel makes a point that a port carrying Thunderbolt 3 should also be cross wired with USB 3.X and Display Port hardware to output those signals as well.
So if you want a monitor that uses a Type-C connector, your looking for a display-port monitor. Which your not likely to find in the portable market yet.
Now that I knew what to look for, re-examination of the text and
shows a couple interesting things: "USB Type-C connectivity with hybrid signal solution for Type-C and Type-A source compatibility (requires a DisplayLink driver for Type-A connection)." So it's implying that it doesn't need a driver for Type-C. And looking at the pictures,
On 24 March 2018 at 08:08, Giles Orr via talk <talk@gtalug.org> wrote: power-only and based pictures there's a
"DisplayPort" icon next to one of the buttons on the front. So ...
My other questions stand:
- how can I figure out what USB protocol (3.0 or 3.1) the type-C connector on my Linux computer supports?
lspci -d ::0c03 -k will display the vendors controller and kernel driver in use.
- (clearer understanding leads to a clearer question here, although I'm still not sure I'm saying it right) does Linux support DisplayPort video over USB-C?
Oops. No usb-c display context for this monitor. This test used the display link binary and a USB 2 adapter on Ubuntu LTS.
https://www.phoronix.com/scan.php?page=article&item=asus-mb1 6ac-zenscreen&num=2
I think the short answer is yes. If you can hard wire a DisplayPort to HDMI adapter cable you must surely be able to sink to the host connections logically as well.
Has somebody done this yet, I don't know.
Since kernel 4.12 there has been development on a state machine for hosting sinks.
e-C-Promotion-Linux-4.15
Power management and signalling are all represented, soft-jacking is another issue.
and-displayport-over-usb-c
*Alternate mode data*
https://github.com/torvalds/linux/blob/master/drivers/usb/typec/tcpm.c
HTH
Thanks Russell, Lennart. I grabbed Fedora's very latest kernel this morning (4.15.12-301.fc27.x86_64) given Russell's point that there's been a lot of new feautures related to this. After a reboot I ran 'lspci' - I have USB3.0, not 3.1. This is backed up by the Zenbook manual. The manual calls the port "USB Type-C/DisplayPort combo port" and says "Use a USB Type-C adapter to connect your Notebook PC to an external display." I didn't find anything more specific than that, but it's promising. It'll probably be a long time before I test it though! I haven't got my head around the spec enough to know: does the fact that it's USB-C guarantee that it can deliver 20v and lots'o-watts to accessories? What about accepting that voltage from a charger? I'd bet that Asus hasn't bothered to set up that port to allow charging through it as the computer also has a dedicated old-style charger/plug combo. -- Giles https://www.gilesorr.com/ gilesorr@gmail.com