Re: [PATCH v4 15/19] media: i2c: add Maxim GMSL2/3 serializer and deserializer drivers

From: Jakub Kostiw
Date: Thu Jun 19 2025 - 14:31:00 EST


Hi Cosmin,

I have tested V4 on Raspberry Pi 5 (v6.15) and I think that I might have found some issues.

MAX96714+MAX96717+IMX219:

Streaming to memory works as expected, however I have encountered issues when I was testing
this with libcamera (streams + meta pad).

To make things work in the first place (tested on V3) I had to create 2 streams - one for image
and one for metadata. Essentialy what I did was setting up routes as follows (for both serializer
and deserializer):

Image stream: [0/0 -> 1/0]
Meta stream: [0/1 -> 1/1]

With that and some extra adjustments on libcamera side I was able to get video stream.

Now, above fails on V4. I belive that this is to due with following line:
max_ser.c:

+ ret = max_validate_tpg_routing(routing);
+ if (ret)
+ return ret;

Routing fails here as (I believe) tpg routing is checked even if tpg is not being routed.
After I commented out this check all worked as before. This was not a problem for deserializer
as such check does not exist there.

Perhaps this check should be conducted only when is_tpg is true?

MAX96724+MAX96717+IMX219:

This setup was also tested by me on V3 (streaming to memory only) and worked as expected. With V4
however, after setting up the pipeline, I am unable to get video stream. No error is reported.
I doubled checked my setup with V3 and it worked flawlessly (with the same configuration scripts).
Streaming simply hangs after VIDIOC_STREAMON. I am able to quickly test V3 and V4 so I can provide
you some further information if needed.

--
Regards
Jakub