Created attachment 131906 [details] dmesg ------------------------------------------------- ==Bug detailed description== -------------------------------------------------- Default configuration (mini DP to DP) + (DP to DP--4K monitor) + (DP to HDMI ++ 4K monitor) + using a MST dongle "sunix" can not boot up 4K display. Using: 1 acer monitor 4K 1 Asus monitor not 4K For this test we use different monitors, and different dongles with the sames results ------------------------------------------------- ==Steps to reproduce== -------------------------------------------------- 1. Connect platform to DP using required dongle 2. Turn device ON -------------------------------------------------- ==Actual results== -------------------------------------------------- one of two monitors do not send image. ------------------------------------------------- ==Expected results== -------------------------------------------------- GUI should be displayed without any issues on 2 monitors -------------------------------------------------- ====================================== Hardware ====================================== platform : BDW motherboard id : NUC5i7RYB form factor : Desktop cpu family : Core i7 cpu family id : 6 cpu information : Intel(R) Core(TM) i7-5557U CPU @ 3.10GHz gpu card : Intel Corporation Iris Graphics 6100 (rev 09) (prog-if 00 [VGA controller]) memory ram : 15.58 GB max memory ram : 16 GB display resolution : 1600x900 cpu thread : 4 cpu core : 2 cpu model : 61 cpu stepping : 4 socket : Socket BGA1168 signature : Type 0, Family 6, Model 61, Stepping 4 hard drive : 111GiB (120GB) current cd clock frequency : 337500 kHz maximum cd clock frequency : 540000 kHz displays connected : DP-2 ====================================== Software ====================================== kernel version : 4.12.0-rc3-drm-tip-ww22-commit-187376e+ architecture : x86_64 os version : Ubuntu 17.04 os codename : zesty kernel driver : i915 bios revision : 5.6 bios release date : 05/11/2017 ====================================== Kernel ====================================== commit: 187376e -------------------------------------------------- Attaching dmesg and xrandr --verbose
Created attachment 131907 [details] verbose
Adding tag into "Whiteboard" field - ReadyForDev *Status is correct *Platform is included *Feature is included *Priority and Severity correctly set *Logs included
The problem seems to be present in SKL as well, apparently is not taking all resolutions (bandwidth)?. All configurations using MST dongle are having the same behavior, it doesn't matter if is a MST stand alone or cascade connected (MST + MST)
Many MST hubs have limitations in terms of either frame rate or max number of lines of resolution. These limitations are not queryable via software. If memory serves, many of the Sunix hubs are limited to resolutions of ~1440 lines. If you could post the specific model number for the Sunix MST hub you are using, I'll try to chase down specifics for you.
Hi, Sure, the MST model is DPD2001 or full model: DisplayPort to Dual DisplayPort Graphics Splitter Black (DPD2001) Actually you can find more information about it on the follow link: Download Datasheet http://www.sunix.com/en/download.php?pid=1720&file=datasheet&file_link=download/datasheet/2014/20141119170512_DPD2001-Datasheet-V12.pdf
Analyzing the hardware specifications of "DisplayPort to Dual DisplayPort Graphics Splitter DPD2001 SUNIX" MST. We have identified that DP 1.2 does not support enough bandwidth over a single link to drive two 4k monitors, and this should not be a mistake anymore. Adding DataSheet URL http://www.sunix.com/en/download.php?pid=1720&file=datasheet&file_link=download/datasheet/2014/20141119170512_DPD2001-Datasheet-V12.pdf
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