[libcamera-devel] Intel IPU3: can't retrieve 3A Auto Exposure (AE) statistics

[Jean-Michel Hautbois]

Hi Sakari, all,

I am currently working with libcamera and trying to make it work on a
IPU3 pipeline (MS Surface Go 2)...
I can set the buffer parameters, thanks to Niklas work, but can't get
the 3A statistics buffer back.
More precisely, the buffers are queued/dequeued but the 'ae_en' bit is
never set to 1, and all the raw buffers are set to '0' values.

I suppose I have missed to set one parameter somewhere, but according to
https://www.kernel.org/doc/html/v5.6/media/uapi/v4l/pixfmt-meta-intel-ipu3.html#c.ipu3_uapi_ae_grid_config
setting the 'ae_en' bit in the ipu3_uapi_ae_grid_config structure should
be enough to trigger ?

I have pushed my (very work in progress) work here:
https://github.com/jhautbois/libcamera/tree/test-fake-ipu3-ipa

I would appreciate feedback on this stuff, as I can't see anything
missing from a user-space perspective right now... :-)

Thanks,
--
Regards,
JM