HDMI screen flicker under heavy load

[Bikeman]

Hi all,

With both the original SD card image and the new one releasesd a few days ago, I get a lot of flicker in the HDMI output. The problem is sporadic and kind of rare if the Parallella is idle, but if you put full load on the CPU, the screen flickers rather constantly, up to once every few seconds, and more. Rather unusable that way. I think it's worse after running any of the epiphany sampes, but I'm not sure.

I use BOINC / Einstein@Home to put load on the CPU cores. I use a TV for HDMI output, FWIW, at HD resolution.

Is it just my Parallella board (rev 1) or are others seeing this as well? It's not a big issue for me since I use SSH or VNC to access the board most of the time, but others might be affected more badly.

To reproduce the problem, I suggest the following:

1) put your board under full CPU load (both cores).

Does it flicker?

2) run one of the epiphany examples, e.g, matmul .

Does flickering start now (even after the Epiphany process has finished).

Cheers
HB

[Claggy]

Yes, I also see flickering under load, also running Boinc, either at Einstein or Albert at home,
Resolution is at 1920*1200 on the 14th March Ubuntu build that came with my Parallellas,
my parallella's are running a self compiled Boinc 7.2.47 rather than the repository build,
I do have a new Ubuntu 14.04 installation done, but not running Boinc on it yet.

My Raspberry Pi, has a worse problem, there the screen Blanks for about a second at a time.

Claggy

[Bikeman]

[shodruk]

Maybe that is caused by traffic jam of the bus.
Try setting the screen resolution 1280x720 instead of 1920x1080.

http://elinux.org/Parallella_Linaro_Nan ... o_1280x720