Draft: fixed the CSI lanes for the avt-auvidea-38491

[sbasei]

@fkesseler

Could you please review if this change will have some side effects and if it should be merged to auvidea box or this would work only for our specific project? Thank you.

[fkesseler]

Hi Sidnei,
thank you for your PR. Can you explain how this fixes your issue? We have several other configurations that use 4 lanes between camera and serializer and only 2 lanes between deserializer and host. Those seem to be working.

The DS90UB953 serializer only supports reception with 832Mbps per lane (with DDR, hence the 400MHz clock), while the DS90UB954 deserializer can output at 1.6Gbps per lane, which makes 4 lanes to 2 lanes range extension possible.

By reducing the camera output to two lanes you end up restricting the video bandwidth more than should be necessary.

[sbasei]

Hi @fkesseler.

Unfortunately, I haven't enough knowledge to follow you in this level of detail. Perhaps, this is some hardware specific limitation we had in the first version of our box. I will try without this changes in the revision 2 of the box we have now and let you know. Meanwhile, if you have another test, I can run and provide you the details.

The error we had before this change was a timeout when streaming from the camera. The device was available in the operating system, but not usable. The logs:

[ 767.947168] ALVIUM 1500 C-500c 1-4d: avt_cropcap:5044: Default crop rect width 2592 [ 768.396611] [RCE] vi5_hwinit: firmware CL2018101701 protocol version 2.2 [ 780.376742] tegra194-vi5 [15c10000.vi](https://15c10000.vi/): no reply from camera processor [ 780.376905] tegra194-vi5 [15c10000.vi](https://15c10000.vi/): uncorr_err: request timed out after 12000 ms [ 780.377078] tegra194-vi5 [15c10000.vi](https://15c10000.vi/): err_rec: attempting to reset the capture channel [ 780.379878] tegra194-vi5 [15c10000.vi](https://15c10000.vi/): err_rec: successfully reset the capture channel [ 781.054854] tegra194-vi5 [15c10000.vi](https://15c10000.vi/): corr_err: discarding frame 0, flags: 0, err_data 0

Cheers.