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hzeller / rpi-rgb-led-matrix

Controlling up to three chains of 64x64, 32x32, 16x32 or similar RGB LED displays using Raspberry Pi GPIO
GNU General Public License v2.0
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Overclocking and Flickering (Reply) #551

Open beikimajid opened 6 years ago

beikimajid commented 6 years ago

Hi according to : #41

I test raspbian with last RT_Kernel but I did not see the difference . With it I see some flicker. (p5 smd & 3 Rows & 6 Cols & passive PCB & 3 parallel).

I even test these conditions: remove overclock setting add overclock setting remove isolcpus=3 in RT-Kernel add isolcpus=3 in RT-Kernel

Are you sure that RT_Kernel is answer to have not flicker?

hzeller commented 6 years ago

RT kernel can improve flickering, but of course not eliminate it if we hit a hardware limit. So far the question is still open if it can create a much better experience than the regular kernel, so these experiments are needed.

Never do overclocking and always use isolcpus independent of the kernel.

You did not describe details to help people reproduce your findings: what compile-time parameters you choose when you compiled the kernel, or if it is a stock kernel, which exact distribution ? What kernel parameters did you choose at boot time (such as NO_HZ) ?

What did you do to induce the flicker? Usually flicker can only be seen these days if you run something in another shell.

russdx commented 6 years ago

I will be trying a RT kernel soon to try and get 100% flicker free experience.

Is it as simple as just running RPI-RGB on a RT kernel with isolcpus=3 or does the RPI-RGB process need to be setup in a way it takes advantage of the RT kernel? ie it says it needs to be real time and do not every interrupt it.

Regards Russell

hzeller commented 6 years ago

Check out the new compile-time option in FIXED_FRAME_MICROSECONDS in lib/Makefile. It will allow to time-buffer glitches created by the rest of the system.

HummingBuddha commented 6 years ago

Hello hzeller I am using a 64x64 32s P2.5 module. I have too much of flicker. I tried "FIXED_FRAME_MICROSECONDS in lib/Makefile" but of no use. Is there any ways to improve the scan rate programatically? In other scan issues you have mentioned not to use 64x64 32S modules as they are slow but I have no other go I am working on a 64x64 P2.5, so pls let me know if there are any solutions for the flickers. And is there any way to compress and accommodate larger image files into the UDP size? And pls help me out in understanding how the UDP size is being calculated and at what size it would override the UDP max value as I got an override at 171x128 for a video wherein it was able to display at 170x128.

Thanks