Precision 7530 & Precision 7730 owner's thread

Discussion in 'Dell Latitude, Vostro, and Precision' started by Aaron44126, Jun 27, 2018.

  1. heikkuri

    heikkuri Notebook Enthusiast

    Reputations:
    2
    Messages:
    15
    Likes Received:
    2
    Trophy Points:
    6
  2. Aaron44126

    Aaron44126 Notebook Prophet

    Reputations:
    790
    Messages:
    4,694
    Likes Received:
    1,462
    Trophy Points:
    231
    It looks like we're ordering three WD19DC docks for the office here. Maybe next week I will be able to post some feedback. The TB18DC might not have the consistent issues that it had early on but it still does enough weird stuff to keep me annoyed.
     
    Lumute likes this.
  3. Lumute

    Lumute Notebook Enthusiast

    Reputations:
    0
    Messages:
    13
    Likes Received:
    4
    Trophy Points:
    6
    Me too, I kind of learned how to operate to avoid issues like unplugging and waiting a couple of minutes before sleeping the OS, etc.

    Interested to see how that new dock performs...
     
  4. jeremyshaw

    jeremyshaw Big time Idiot

    Reputations:
    791
    Messages:
    3,210
    Likes Received:
    230
    Trophy Points:
    131
    EDIT: I don't have a Precision of any sort, only a XPS15 7590. I was considering a 7540 at one point, and the associated dock. I did buy the WD19 130W for my XPS15. I didn't get the WD19 TB, solely due to my frustrations with getting TB3 docking and networking to work on my Thinkpad X1C6. These issues are not nearly as severe with my XPS15, though some still exist.







    The only real annoyance I have against the WD19DC is it doesn't do TB3 passthrough, since it's dual USB-C, without any TB3 link.

    However, I was able to confirm that a single USB-C link (whether using the single USB-C module, or a single link on the Dual Cable module) will still allow for 3 monitors (DP, DP, HDMI), so long as the 3 monitors fall under the bandwidth limit for a 2 lane HBR2 DP connection.

    That being said, outside of using, say, three 1280x1024 monitors, there isn't any real use to this information. Even a QHD + FHD 60Hz 4:4:4 SDR setup would exceed the bandwidth required. Mental math seems to say 2 FHD + one HD (likely projector?) would be doable, or 2 FHD + one of the 1280x1024 monitors I mentioned earlier.

    Now that I am really curious, I should test this dock with a Nvidia USB-C Virtuallink output, to see if the dock can actually take advantage of DP 1.4 and drive at HBR3 rates. It would be just enough to support one 4K60 4:4:4 SDR monitor.

    The literature seems to imply this for the docks, but it requires a rather liberal reading of it. Also implies DSC support, though I don't know if it's just being passed through, or if the dock actually is capable of decompressing it for non-DSC monitors. Probably the former.

    It really would improve the longevity of these docks in my mind, and would really make the upgradability a much greater factor, IMO. Though, I haven't actually been able to find the TB3 module for sale.
     
  5. Aaron44126

    Aaron44126 Notebook Prophet

    Reputations:
    790
    Messages:
    4,694
    Likes Received:
    1,462
    Trophy Points:
    231
    The WD19 docks (aside from the TB one) seem to be basically a USB hub that hosts the non-display devices (USB ports, with internally-attached USB audio and USB Ethernet devices) plus a DisplayPort-over-USBC connection for the displays. There is no ASMedia USB controller / PCIe nonsense. Yes, it does not offer a Thunderbolt port and the gobbles both of the ports on the system, so it's a non-starter if you also need to attach a Thunderbolt device. But, I don't have anything Thunderbolt to plug in, I just need a solid display/network/audio/keyboard/mouse connection.

    The old WD15 docks were like this as well (USB hub + DisplayPort). I used one for a while with zero issues. I actually switched to the WD15 after trying the TB15 and having a disastrous experience. Since I upgraded to 4K external displays, though, I have been stuck on TB16 and more recently TB18DC because the WD15 doesn't have the bandwidth for dual 4K 60Hz. @Dell-Mano_G did confirm in the 7540/7740 thread that the WD19DC can support dual 4K at 60 Hz.

    Unlike the TB18DC, the WD19DC appears to use both of the connections for data, which is part of the reason for the display bandwidth increase over the WD15 dock. The TB18DC only uses one of the Thunderbolt ports for data and the other one is just for extra power.

    Anyway. Here's hoping that it actually can run 2x4K60 and otherwise operates as seamlessly as the WD15 did. Find out soon. :)
     
    jeremyshaw likes this.
  6. jeremyshaw

    jeremyshaw Big time Idiot

    Reputations:
    791
    Messages:
    3,210
    Likes Received:
    230
    Trophy Points:
    131
    yeah, the WD19 (vanilla) uses a Slimport chip that does the USB-C Alt mode conversion. The specific model number doesn't pull up any datasheets.

    A single USB-C connection has 4 high speed pairs. In the vanilla WD19 two pairs are used for DisplayPort, two are used for the USB 3.0 high speed data (one for each direction). DP usually has four high speed lanes, so only running two limits the bandwidth for each connection.

    Since the manual implies DP1.4+DSC support for the WD19DC, I'd expect the setup to be capable of handling 2 4k60 monitors. This would mean at least one of the USB-C ports on the Latitude 7000 series is wired to the Nvidia dGPU*, since the Intel IGP is limited to DP 1.2 (HBR2), and it doesn't have the data rate necessary to support a twin 4k60 + USB3.0 setup, even with two USB-C connections. For the WD19DC, I'd venture one of the cables handles two DP 1.4 (HBR3) lanes and USB3.0. This would be enough to support the dock and one 4k60 SDR monitor. The second cable would have all four DP 1.4 lanes, allowing another two 4k60 SDR monitors. With HDR, the datarate needed for 4k60 4:4:4 HDR exceeds what two DP HBR3 lanes can support, so support may be iffy (without going into details/guesses).

    I do very much like the WD19 so far. Definitely trouble-free in the few days I've been using it. The power button seems to like longer presses (to wake a sleeping machine), but it has been consistent and reliable so far. Almost like an actual port replicator dock, which is the first time I have been able to say that for any of the USB-C/TB3 docks, hubs, and dongles I have.


    *Checking the specs, yes, the dGPU is wired to the USB-C video outputs, yay! DP 1.4 is supported via the USB-C connections, and running at least two, upto three, 4k60 SDR displays is practically guaranteed to work.

    https://www.dell.com/support/manual...15a91f-1cbf-43d0-845b-aec6eb03f40f&lang=en-us
     
    Last edited: Jul 24, 2019
  7. Aaron44126

    Aaron44126 Notebook Prophet

    Reputations:
    790
    Messages:
    4,694
    Likes Received:
    1,462
    Trophy Points:
    231
    I have played with this a little. If you have graphics switching off or the "discrete graphics output mode" on then the USB-C ports will be wired to the dGPU for display output. If you have graphics switching on and "discrete graphics output mode" off then they will be wired to the Intel GPU. Same goes for the other ports on the back (HDMI and mDP).

    However there seems to be some dynamic switching going on. I have two 4K displays plus the internal display (three total) and I have it set up with Optimus so that they all work off of the Intel GPU (for simplicity of setup). A coworker has the same setup but an extra 1080p display connected as well, so four monitors total, and one of his monitors gets routed out via the NVIDIA dGPU, as the Intel GPU only supports three displays. I've confirmed which monitors are hooked up to which GPU with the Device Manager "View -> Devices by connection" tree.

    [Edit]
    XPS15 wouldn't have a BIOS setting to disable graphics switching but I think it still might have the discrete graphics output mode setting? Not sure. Precision 7000 series is more configurable for graphics output.
     
    Last edited: Jul 24, 2019
    jeremyshaw likes this.
  8. jeremyshaw

    jeremyshaw Big time Idiot

    Reputations:
    791
    Messages:
    3,210
    Likes Received:
    230
    Trophy Points:
    131
    Yeah, the Intel IGP is limited to 3 active outputs. Thanks for your insight into the display routing w.r.t. 3-4 displays.




    The reason why I bring up the DP1.2, DP 1.4, and USB-C pair/lane allocations is I believe dual 4k60 SDR monitors will not work via the allocations that I think are possible via DP 1.2 on the WD19DC. It should need DP1.4 for that, which will basically require the Nvidia dGPU to drive one or more of the USB-C outputs.

    That being said, the part I mentioned about "(without going into detail/guesses)" was basically a speculation into the ability of the USB-C IC on the dock, USB-C ICs in the laptop, USB-C Alt mode, or DP to allocate DP lanes for 2 monitors across 2 different USB-C connections. Specifically, with DP 1.2, 4k60 requires 12.54Gbps of bandwidth, and DP 1.2 can only serve 17.28Gbps of effective data across its 4 lanes. In the best case setup for the WD19DC hub, there would be 2 + 4 lanes of DP available across the 2 USB-C cables. In DP 1.2, at least three lanes are needed to drive 4k60 SDR 4:4:4. However, I know for DP 1.0, the only possible allocations were 1, 2, & 4 lanes. I do not know if the current components/specs are smart enough to allocate 3+3 lanes across 2+4 available lanes (across 2 cables!). With DP 1.4, however, this becomes a moot point. 2 lanes are all that's needed to support a 4k60 SDR 4:4:4 monitor's bandwidth appetite, and there should be enough lanes/bandwidth for three 4k60 SDR 4:4:4 outputs (indeed, this correlates directly with what the dock's specification claims).

    With HDR and higher frame rates, all of that goes out the window.

    Basically, I am very curious if the Nvidia dGPU is forced on, just to drive your dual monitor setup via USB-C. The curiosity is purely academic (figure of speech). When you get your WD19DC dock, may you please report back on this little bit of information? Thank you very much!
     
  9. Aaron44126

    Aaron44126 Notebook Prophet

    Reputations:
    790
    Messages:
    4,694
    Likes Received:
    1,462
    Trophy Points:
    231
    Yes for sure, I am interested to see as well.
     
    jeremyshaw likes this.
  10. jeremyshaw

    jeremyshaw Big time Idiot

    Reputations:
    791
    Messages:
    3,210
    Likes Received:
    230
    Trophy Points:
    131
    You are right, the XPS 15 (7590) does not have this option. I'd guess it's probably due to the lack of a mux.

    After reading a bit more on the WD19DC manual (also the WD19TB manual), there are some stipulations for display configurations (page 18 for the WD19DC manual's table).

    https://topics-cdn.dell.com/pdf/dell-wd19dc-dock_users-guide2_en-us.pdf

    It appears the USB-C DP Alt Mode port shares its display interface with the HDMI port, so it's an either-or situation with those two. So that means only 3 displays can be used at once on the non-TB3 versions of the dock (TB3 version has an extra TB3 port which allows for quad display configurations). I have no clue how MST works into this, but from what I can understand, it won't increase the max number of supported displays.

    DP 1.4 / HBR3 is basically confirmed to be supported, and one of the notes do seem to imply the dGPU is required for such support in current systems.

    I'm pretty happy, as this does seem like Dell has designed this dock to be useful for some time to come.
     
Loading...

Share This Page