Article Number: 000131916
UltraSharp U2515H / U2715H Loses Video During Boot-Up or Power Save Recovery or Monitor Screen Flashing Intermittently While On
Summary: Steps for resolving video issues on the UltraSharp U2515H and U2715H monitors.
Article Content
Symptoms
This article provides the information about "UltraSharp U2515H/U2715H loses video during boot-up, or power save recovery or monitor screen flashing intermittently while on."
Cause
U2515H and U2715H Monitor Flashing, Blanking Out or Going Black
Dell U2515H or U2715H displays connected via DisplayPort (DP) directly to a docking station and not daisy chained may intermittently flash or show a black screen. This also happens during boot-up and during Power Save recovery.
Powering off the display and powering it back on would restore the display until the issue re-occurred.
Updating the BIOS and graphic adapter drivers has no effect on the issue, nor did changing DisplayPort and mini-DisplayPort cables.
Resolution
Change DisplayPort Mode
Note: Before changing the DisplayPort setting of your display, ensure that your graphics adapter supports the DisplayPort 1.2 standard. If the graphics adapter does not, your screen will not display an image.
This workaround of changing the default DisplayPort mode in the U2515H and U2715H On-Screen Display (OSD) and enabling DisplayPort 1.2. (Figure 1)
Figure 1 - Enabling DisplayPort 1.2 in the On-Screen Display (OSD).
Note: DisplayPort version 1.2 doubles the effective bandwidth of DisplayPort 1.0 to 17.28 Gb/s in High bit rate 2 (HBR2) mode. This allows increased resolutions, higher refresh rates, and greater color depth. Other improvements include multiple independent video streams (daisy-chain connection with multiple monitors) called Multi-Stream Transport, facilities for stereoscopic 3D, increased AUX channel bandwidth (from 1 Mb/s to 720 Mb/s). (https://en.wikipedia.org/wiki/DisplayPort 
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If you need to reset the display to DisplayPort 1.1a mode when the display is not showing an image, use the following steps (Figure 2):
Figure 2 - How to change the input select option in the On-Screen Display (OSD) menu.
On systems equipped with an MST Hub, updating the MST firmware is also recommended. You can download the firmware update (if available) from the Dell Support Website.
If you have further questions about this article, contact Dell Technical Support.
Article Properties
Affected Product
Dell U2515H, Dell U2715H, Latitude E5250/5250, Latitude E7450
Last Published Date
13 May 2021
Version
4
Article Type
Solution