Static / snow on external display when waking up Mac

Question

I have a Philips 222E display connected via a mini-DP to DVI adapter and DVI cable to a Macbook Air (mid-2011).

Every time that the MBA wakes from sleep, the display shows this static:

The static is replaced with the proper desktop image after around 20 seconds, or after a power cycling the display (which could take only 10 seconds but is highly annoying just the same.)

Things I tried and their results:

1. A different display (LG) - no static
2. A different computer (Mac Mini) - no static
3. Different adapter and DVI cable - static remains
4. When booting the MBA (not rebooting) - no static
5. When disconnecting and reconnecting the 222E to the MBA - no static

Answer 1

I've been investigating a little bit and would be good for you guys have a try with this steps. The steps are written for a different type of Display, but can get the idea:

• Under "SIZE & POSITION" menu, go to "Image Size" and set to "Screen Fit"

• Under "SETUP & RESET" menu (down on the second page with my model), go to "Auto Source" and set to "Manual"

• Finally,still under the same "SETUP & RESET" menu page, go to "PC/AV Mode" and set to "AV"

Bingo! Now when the computer wakes up from sleep, the screens are going back on like a charm!

Here's the source:

https://discussions.apple.com/message/13221480#13221480

Answer 2

I had similar issues (exactly the same static problems) with a device that did not support HDCP negotiation (High Bandwidth Digital Content Protection) properly whenever I woke the device up from standby (in my case a Sky+/BenQ monitor combination).

So what's the cause of static? As per this site (though I copy only for the HDCP explanation I appreciate it's not relevant to your devices):

If HDCP is not detected

If HDCP authentication does not succeed, you may see one of the following symptoms:

• A message may appear on your television stating "This content requires HDCP for playback. HDCP isn't supported by your HDMI connection."

• You may see periodic bands of static, or full screen static, flashing across your TV screen.

https://support.apple.com/en-us/HT201310

I think when you resume from sleep it doesn't do a full HDCP negotiation again.. but power-cycling the display forces it to.

HDCP can be fraught with all sorts of weird incompatibility issues:

Anyway, the new TV apparently keeps the HDMI connection active when it's powered off; but, it doesn't keep the HDCP handshake active. So, TiVo sees that as a bad HDMI connection, and refuses to show any video signal except for an HDMI error; this shows up on the TV that's connected by component cables. I can get video over component if I turn the TV on or if I unplug the main TV so that the HDMI connection is not at all active, but in the main TV's power-off mode all I get over component is the HDMI warning message.

http://www.avsforum.com/forum/166-lcd-flat-panel-displays/1432643-hdcp-hdmi-power-standby-mode-suggestions.html

It's hard to say which is not following HDCP negotiation properly, but it sounds like either Apple or the monitor manufacturer need to update their HDCP software (check the Philips site for a software/firmware upgrade at least?) to be more compatible with eachother and sometimes the adapters can complicate things too so try to stick with the ports the device expects to see the connections on :-).

There are HDCP strippers that will fake HDCP authentication so you can then plug into devices that may not support it correctly, but I'm not sure whether it's appropriate to discuss these on this site.