v4l2 디버깅을 위해서는 아래와 같이 설정해주면 dmesg에 출력되게 된다.
# echo 0x1f > /sys/class/video4linux/video1/dev_debug |
[링크 : https://stackoverflow.com/questions/24330671/v4l2-kernel-space-debugging]
guvcview 유틸리티를 이용해서 테스트.
하단의 exposure, auto / (absolute) / Auto Priority 관련 설정을 바꿀때 나오는 값 확인
Exposure, Auto - Aperture Priority Mode
[ 1041.346246] video2: VIDIOC_DQEVENT: type=0x3, pending=0, sequence=13, id=10094850, timestamp=1040.623934215 [ 1041.346259] changes=0x3, type=1, value=3216, flags=0x10, minimum=39, maximum=10000, step=1, default_value=156 [ 1041.346272] video2: VIDIOC_DQEVENT: error -2: type=0x0, pending=0, sequence=0, id=0, timestamp=0.000000000 |
Exposure, Auto - Manual / 3216
[ 1128.312839] video2: VIDIOC_S_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0901/0x3 [ 1128.312866] video2: VIDIOC_G_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0901/0x3 |
Exposure (Absolute)
[ 621.732496] video2: VIDIOC_S_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xe55 [ 621.733321] video2: VIDIOC_G_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xe55 [ 621.749803] video2: VIDIOC_S_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xe56 [ 621.750586] video2: VIDIOC_G_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xe56 [ 621.784790] video2: VIDIOC_S_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xcbf [ 621.785731] video2: VIDIOC_G_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xcbf [ 621.802333] video2: VIDIOC_S_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xcc0 [ 621.803150] video2: VIDIOC_G_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xcc0 [ 621.833353] video2: VIDIOC_S_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xc90 [ 621.834204] video2: VIDIOC_G_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xc90 [ 621.849972] video2: VIDIOC_S_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xc90 [ 621.850772] video2: VIDIOC_G_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0902/0xc90 |
Exposure, Auto Priority (선택)
[ 1464.855961] video2: VIDIOC_S_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0903/0x1 [ 1464.855989] video2: VIDIOC_G_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0903/0x1 |
Exposure, Auto Priority (미선택)
[ 1519.669796] video2: VIDIOC_S_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0903/0x0 [ 1519.669856] video2: VIDIOC_G_EXT_CTRLS: which=0x9a0000, count=1, error_idx=0, request_fd=0, id/val=0x9a0903/0x0 |
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