topic Re: imx8m plus camera input resolution not changing in i.MX Processors

imx8m plus camera input resolution not changing

dennis3 — Wed, 18 May 2022 21:07:35 GMT

On our previous processor (imx8m quad), our camera driver received v4l2 ioctl commands (via <dev>_s_parm) to set the desired video mode with the V4L2_BUF_TYPE_VIDEO_CAPTURE ioctl. The driver would pass in parm.capture.capturemode that was one of the modes reported earlier in get enum_framesizes ioctl.

Our driver v4l2 subdev driver hasn't changed much between the two different kernels. Now, on the imx8m plus, it looks like the capture ioctl never get called though. Instead. we get an <dev>_s_stream command but then the sensor is always left in the same default state for it's resolution. The output resolution looks to be being scaled by the ISI layer instead. For example, if I select via the camera api to stream 640x480, I'll see something like this in the dmesg output:

mxc-isi 32e00000.isi: input_size(2880,2016), output_size(640,480)

So it appears I'm missing something on how to configure in the HAL or driver layer that will allow the driver to change the capture size from the image sensor. Any hints where this might be?

Re: imx8m plus camera input resolution not changing

joanxie — Thu, 19 May 2022 05:47:29 GMT

if you want to use v4l2 ctrl to change the resolution, you can try to use "v4l2-ctl -d /dev/video0 --verbose --set-fmt-video=width=xx,height=xx"

for ISI drivers, pls find the source code

"https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/staging/media/imx/imx8-isi-cap.c?h=lf-5.15.y"

Re: imx8m plus camera input resolution not changing

dennis3 — Thu, 19 May 2022 15:00:32 GMT

Thanks @joanxie

So we're using Android and don't have the v4l2 controls. Are you saying if we wish this functionality I need to modify the driver?

Re: imx8m plus camera input resolution not changing

joanxie — Sat, 21 May 2022 12:24:03 GMT

android share the same linux kernel, you can find frame size setting in the ISI driver as below:

"https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/staging/media/imx/imx8-isi-cap.c?h=lf-5.15.y"