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

[Alexander Stein]

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?

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