drivers: video: ov7670/smartdma: red pattern instead of image

[josuah]

Describe the bug

The FRDM-MCXN connected with the OV7670 camera gives unexpected output with red/white color stripes.

To Reproduce

I used UVC but a display shield might work as well:

git remote add tvai https://github.com/tinyvision-ai-inc/zephyr/
git fetch tvai
git cherry-pick tvai/pr-usb-uvc~4..tvai/pr-usb-uvc
git cherry-pick tvai/pr-frdm-mcxn947-shield~4..tvai/pr-frdm-mcxn947-shield
west build --board frdm_mcxn947/mcxn947/cpu0 --shield dvp_20pin_ov7670 samples/subsys/usb/uvc/

Expected behavior

The correct color image data output with mostly dark pixels (when ambient light is off) instead of red.

Impact

None: uses features not yet merged for bug reproduction such as UVC.

Logs and console output

The host selected the RGBP (RGB565) pixel format (last listed wins):

...
[176148.509184] usb 1-4.3.1.2: Trying format 0x39555659 (YVU9): 320x240
[176148.509188] usb 1-4.3.1.2: Using default frame interval 2026253.6 us (0.4 fps)
[176148.510307] usb 1-4.3.1.2: Trying format 0x4f424752 (RGBO): 320x240
[176148.510312] usb 1-4.3.1.2: Using default frame interval 2026253.6 us (0.4 fps)
[176148.511374] usb 1-4.3.1.2: Trying format 0x51424752 (RGBQ): 320x240
[176148.511377] usb 1-4.3.1.2: Using default frame interval 2026253.6 us (0.4 fps)
[176148.512321] usb 1-4.3.1.2: Trying format 0x50424752 (RGBP): 320x240
[176148.512326] usb 1-4.3.1.2: Using default frame interval 2026253.6 us (0.4 fps)
[176148.514082] usb 1-4.3.1.2: uvc_v4l2_mmap
[176148.514105] usb 1-4.3.1.2: uvc_v4l2_mmap
[176148.514118] usb 1-4.3.1.2: uvc_v4l2_mmap
[176148.514131] usb 1-4.3.1.2: uvc_v4l2_mmap
[176148.514144] usb 1-4.3.1.2: uvc_v4l2_mmap
[176148.514162] usb 1-4.3.1.2: uvc_v4l2_mmap
...
[176148.514440] usb 1-4.3.1.2: uvc_v4l2_mmap
[176148.514449] usb 1-4.3.1.2: uvc_v4l2_mmap
[176148.517194] usb 1-4.3.1.2: Allocated 5 URB buffers of 32x512 bytes each
[176148.780992] usb 1-4.3.1.2: Frame complete (EOF found)
[176148.804185] usb 1-4.3.1.2: frame 1 stats: 0/8/8 packets, 0/0/0 pts (!early !initial), 0/0 scr, last pts/stc/sof 0/0/0
[176148.915010] usb 1-4.3.1.2: Frame complete (EOF found)
[176148.938116] usb 1-4.3.1.2: frame 2 stats: 0/8/8 packets, 0/0/0 pts (!early !initial), 0/0 scr, last pts/stc/sof 0/0/0
[176149.048189] usb 1-4.3.1.2: Frame complete (EOF found)
[176149.071250] usb 1-4.3.1.2: frame 3 stats: 0/8/8 packets, 0/0/0 pts (!early !initial), 0/0 scr, last pts/stc/sof 0/0/0
[176149.180989] usb 1-4.3.1.2: Frame complete (EOF found)
[176149.204179] usb 1-4.3.1.2: frame 4 stats: 0/8/8 packets, 0/0/0 pts (!early !initial), 0/0 scr, last pts/stc/sof 0/0/0
[176149.315186] usb 1-4.3.1.2: Frame complete (EOF found)
...

Environment (please complete the following information):

• OS: (e.g. Linux, MacOS, Windows)
• Toolchain (e.g Zephyr SDK, ...)
• Commit SHA or Version used

Additional context

Single frame:

Multiple frames converted to GIF. The effect of turning the light on: