Overclocking and Flickering

[Saij]

Hi,

played a little bit with overclocking and determined that overclocking result in flickering.

Here is my config.txt (only overclocking part)

arm_freq=1000
sdram_freq=500
core_freq=500
over_voltage=2
force_turbo=1
disable_splash=1
boot_delay=0
gpu_mem=16

RPi is stable and no problems with cyclictest. But as soon as I run led-matrix it will flicker. Even with -p 4

A test shows that after removing the overclock settings matrix just works fine again.
Just as information

Greetings
Saij

[hzeller]

Interesting. In the master or the pwm branch ?

[Saij]

Used the PWM branch

[Saij]

Used also 3.18.9 RT5 kernel

[hzeller]

Interesting. Maybe the transition between the two clock-domains is affected (the ARM clock domain and the PWM unit are separated by a queue).

[hzeller]

Speaking of the RT kernel: did you see any difference ?

[Saij]

Not really
But it seems to Run smoother.
Without it you could sometimes see some flicker.
With it no flicker at all

[combs]

I have a feeling this may have changed in the intervening years?