5870 Video Issues (flashing black, "snow")

[adversus]

Hey all,

My Mac Pro had been sitting idle for about 2 weeks while I was traveling on business. It was working since I was able to Back to My Mac it while I was away.

When I got back I turned my monitor on rebooted to install some recent updates. Once that was done, after about 30 seconds the screen started going black for 10 seconds or so, then coming back. My monitor never lost signal, the video just went black. After doing this for about a minute (10 seconds black, on for about 10 seconds, etc.) a brief splash of digital noise (like the old white noise on an old TV) appeared in between the black/non-black splashes.

I hit the power button and put the machine to sleep, woke it back up, and it hasn't come back since. Should I worry about this? Has this happened to anybody before?

 

[xgman]

Hey all,

My Mac Pro had been sitting idle for about 2 weeks while I was traveling on business. It was working since I was able to Back to My Mac it while I was away.

When I got back I turned my monitor on rebooted to install some recent updates. Once that was done, after about 30 seconds the screen started going black for 10 seconds or so, then coming back. My monitor never lost signal, the video just went black. After doing this for about a minute (10 seconds black, on for about 10 seconds, etc.) a brief splash of digital noise (like the old white noise on an old TV) appeared in between the black/non-black splashes.

I hit the power button and put the machine to sleep, woke it back up, and it hasn't come back since. Should I worry about this? Has this happened to anybody before?

This happens to a good number of people and even on a MBP or Mini when using an external monitor. I had it start happening on my 2010 MP with a 5870 on a dvi to dvi cable to a 30" dell, both ob Snow Lep and Lion. A new 5870 vid card sent by Apple didn't help. A new dvi-d cable didn't help. Added a new monitor using only displayport connectors and so far hasn't happened. Some think it is a "HDCP handshake" issue. Prior to this I set up a hot corner to put the monitor instantly to sleep and back again and that would cure it temporarily without having to unplug and replug the dvi cable, which would also reset things back to normal, so I think it is probably a "handshake" timing issue of some sort.

 

[adversus]

Thanks for the response!

It hasn't happened since so I'm not that concerned, but good to know it may be a known issue. Makes sense then that putting the machine to sleep would re-set the HDCP connection.