Necessary in my case, power supply

I have the 3-port switch with remote control.
After delivery I have connected the switch immediately and initially it worked very well. But after 10 minutes of operation set the image repeatedly. At first I thought it was a failure, and sent back to the switch and ordered a second. But here there were the same problems. Then I have the support CSL written. Here I got the hint that there appears to devices that do not with sufficient supply voltage via the HDMI cable to the switch and such problems can come along. I was recommended the following power supply:

This works just fine, and the switch is running without any problems since then. Nevertheless, I have deducted a star because almost doubled along with the power supply, the price and I would have liked clearer indications in the description that it is not so rare that a power supply is needed (the only reference I can find could was that no AC adapter is required). I run the switch on an LG TV, a Sony Blue Ray player and a Raspberry Pi. Up to the raspberry are really mass products and no Noname devices of dubious origin and of which I would have expected that the power supply should be sufficient. It may be that these devices do not meet the HDMI specification, but it is then safely apply to many devices.

Overall, however, a great switch, you have to only be clear, possibly still need a power supply. Image quality and Fernbedinung are excellent.