Re: (EXT) [BUG] media: imx: imx7-media-csi issue with vb2 is hanging / freezing the system

[Martin Kepplinger]

Am 12. November 2021 13:40:43 MEZ schrieb Alexander Stein <alexander.stein at ew.tq-group.com>:
>Hello Martin,
>
>Am Freitag, dem 12.11.2021 um 12:23 +0100 schrieb Martin Kepplinger:
>> hi Laurent and all who it may concern,
>> 
>> Ever since I switches to using imx7-media-csi on imx8mq I have seen a
>> bug that hangs /freezes the system so that I can't really save a trace
>> or get logs for it. It happens not every time when starting streaming,
>> but sometimes - when starting to stream frames.
>> 
>> It kind of looks like a lock not released or something similar, but
>> some race condition might happen since it's happening every 2 to 10
>> times.
>> 
>> For me, when it fails, it fails the first time when starting to stream
>> after rebooting. If it succeeds that first time, it continues to
>> succeed, until I reboot.
>
>When I read your description I was immediately reminded to this post on
>NXP forums [1].
>I do not know if this is what is happening to you, but it sounds
>somewhat similar. There is also an errata in post [2] describing some
>backgrounds. Later posts also describe that apparently only CSI port 1
>is affected, but CSI port 2 is not.
>Do you have the possibility to test CSI port 2?

yes but I can only say that csi port 2 behaves better while I have seen a lockup there too. That too matches your links' issue description. I dont have logs from port 2 yet.

Thanks a lot, there's at least something new to test I think. Let's see whether a kernel thread would work instead of an m4 program.

But why haven't I ever seen the problem on the mx6s_capture nxp driver? That doesn't fit the picture yet for me.

>
>Best regards,
>Alexander
>
>[1] https://community.nxp.com/t5/i-MX-Processors/IMX8MQ-MIPI-CSI2-Base-address-switching-change-error/m-p/1218063
>[2] https://community.nxp.com/t5/i-MX-Processors/IMX8MQ-MIPI-CSI2-Base-address-switching-change-error/m-p/1216509/highlight/true#M167970
>