i.mx6 PCIE bandwidth issue

[linya]

I test tw6869 on i.mx6 , it work well with 6 D1 channel at the same time.
but it will encounter FIFO overflow warning while open 7 or 8 D1 channel.
It also work well with 8 channel while scale some channel with half size.

I also check message from:
https://community.nxp.com/docs/DOC-95143
It's seem that no one could enable 8 D1 channel at the same time.
I suppose that is i.mx6 PCIE bandwidth issue.
I estimate the bandwidth only 128M Byte instead of 500M PCIE 2.0 standerd

How to enable 8 channel D1 on i.mx6?

[merttml13]

Hello Lin and Halil,

I am trying to 6 videos recording at the same time. But when I try even 4 videos same time, I face same problem with you I think.

Here is my error line ;

tw6869 0000:01:00.0: tw6869_vch_dma_wait: vch3: video not present
tw6869 0000:01:00.0: tw6869_vch_dma_wait: vch0: video not present
tw6869 0000:01:00.0: tw6869_vch_dma_wait: vch2: video not present
tw6869 0000:01:00.0: tw6869_vch_dma_wait: vch1: video not present
tw6869 0000:01:00.0: tw6869_dma_reset: DMA 0
tw6869 0000:01:00.0: tw6869_dma_reset: DMA 1
tw6869 0000:01:00.0: tw6869_dma_reset: DMA 2
tw6869 0000:01:00.0: tw6869_dma_reset: DMA 3

Could you please share your 6 D1 code or could you please help me ? here is my code;

gst-launch-1.0 -evvvv v4l2src device=/dev/video0 ! queue2 ! videoscale ! "video/x-raw, width=720, height=576, framerate=25/1" ! \
imxipuvideotransform ! imxvpuenc_h264 bitrate=6500 ! avimux ! \
filesink location=/home/root/test0.avi \
v4l2src device=/dev/video1 ! queue2 ! videoscale ! "video/x-raw, width=720, height=576, framerate=25/1" ! \
imxipuvideotransform ! imxvpuenc_h264 bitrate=6500 ! avimux ! \
filesink location=/home/root/test1.avi \
v4l2src device=/dev/video2 ! queue2 ! videoscale ! "video/x-raw, width=720, height=576, framerate=25/1" ! \
imxipuvideotransform ! imxvpuenc_h264 bitrate=6500 ! avimux ! \
filesink location=/home/root/test2.avi \
v4l2src device=/dev/video3 ! queue2 ! videoscale ! "video/x-raw, width=720, height=576, framerate=25/1" ! \
imxipuvideotransform ! imxvpuenc_h264 bitrate=6500 ! avimux ! \
filesink location=/home/root/test3.avi \
v4l2src device=/dev/video4 ! queue2 ! videoscale ! "video/x-raw, width=720, height=576, framerate=25/1" ! \
imxipuvideotransform ! imxvpuenc_h264 bitrate=6500 ! avimux ! \
filesink location=/home/root/test4.avi \
v4l2src device=/dev/video5 ! queue2 ! videoscale ! "video/x-raw, width=720, height=576, framerate=25/1" ! \
imxipuvideotransform ! imxvpuenc_h264 bitrate=6500 ! avimux ! \
filesink location=/home/root/test5.avi

PS: I tried with using imxipucompositor and tee command, these ones cannot handle with 3 videos same time even.

Best Regards.

Mert TEMEL

[igorpadykov · Accepted solution]

Hi lin

your assumptions may be correct as it may require about 30MB/s per channel.

Please refer to PCIe bandwidth measurements on

https://community.nxp.com/docs/DOC-95014
~100MB/s ARM core used as the bus master, and cache is enabled    
~211MB/s IPU used as the bus master(DMA)

To enable 8 channel D1 one can try to decrease channel fps.

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[halilgoektepe]

Hi,

I have the same issue. After starting 8. video channel FIFO overflow bits are set. Video streming with 7 channels is woking. 

Is the PCIe bandwidth the reason for this issue? Is there any bug fix for it?

Best regards,

Halil Göktepe

h.goektepe@gateconnect.de