I got a Lenovo USB port replicator (model no: K33415) with DisplayLink VGA. When I plug it into my Lenovo laptop (with no display attached to the dock yet), USB hub and audio devices from the dock are found but the DisplayLink device initialization gets an error. All bytes in vendor firmware descriptor and EDID seem to be zero.

Is it something wrong with the device, Linux USB stack or UDL driver?

[379953.534772] usb 1-3.4: new high-speed USB device number 23 using xhci_hcd [379953.630502] usb 1-3.4: New USB device found, idVendor=17e9, idProduct=01e0, bcdDevice= 0.03 [379953.635493] usb 1-3.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [379953.640411] usb 1-3.4: Product: Lenovo Enhanced USB Port Replicator [379953.645573] usb 1-3.4: Manufacturer: DisplayLink [379953.650430] usb 1-3.4: SerialNumber: 01>0-128530 [379953.662128] [drm] vendor descriptor length:e0 data:00 00 00 00 00 00 00 00 00 00 00 [379953.667129] [drm:udl_init.cold [udl]] *ERROR* Unrecognized vendor firmware descriptor [379953.673031] [drm] Initialized udl 0.0.1 20120220 for 1-3.4:1.0 on minor 1 [379953.677693] [drm] Initialized udl on minor 1 [379953.733025] udl 1-3.4:1.0: [drm] DVI-I-1: EDID is invalid: [379953.735019] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.737014] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.739061] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.741086] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.743170] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.745163] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.747176] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.749093] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.751015] udl 1-3.4:1.0: [drm] Cannot find any crtc or sizes [379953.753565] [drm] vendor descriptor length:e0 data:00 00 00 00 00 00 00 00 00 00 00 [379953.755501] [drm:udl_init.cold [udl]] *ERROR* Unrecognized vendor firmware descriptor [379953.758261] [drm] Initialized udl 0.0.1 20120220 for 1-3.4:1.1 on minor 3 [379953.760405] [drm] Initialized udl on minor 3 [379953.827661] udl 1-3.4:1.1: [drm] DVI-I-3: EDID is invalid: [379953.832758] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.838083] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.843553] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.848803] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.853151] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.856164] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.858381] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.860334] [00] ZERO 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [379953.862199] udl 1-3.4:1.1: [drm] Cannot find any crtc or sizes [379964.084865] udl 1-3.4:1.0: [drm] Cannot find any crtc or sizes [379964.089921] udl 1-3.4:1.1: [drm] Cannot find any crtc or sizes