If an exposure time change adjusts the vblanking limits, and we set both
VBLANK and EXPOSURE controls through the VIDIOC_S_EXT_CTRLS ioctl, the
latter may fail if the value is outside of the limits calculated by the
old VBLANK value. This is a limitation in V4L2 and cannot be fixed by
setting VBLANK before EXPOSURE in a single VIDIOC_S_EXT_CTRLS ioctl.
The workaround here is to have the DelayedControls object mark the
VBLANK control as "priority write", which then write VBLANK separately
from (and ahead of) any other controls. This way, the sensor driver will
update the EXPOSURE control with new limits before the new values is
presented, and will thus be seen as valid.
To support this, a new struct DelayedControls::ControlParams is used in
the constructor to provide the control delay value as well as the
priority write flag.
Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Tested-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Tested-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
[Kieran: Fix up trivial comments, merge conflicts]
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Add a test case for DelayedControls that exercises the setting of
controls and reading back what controls were used for a particular
frame. Also exercise corner cases such as a V4L2 device that does not
reset its sequence number to 0 at stream on and sequence number wrapping
around the uint32_t value space.
Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
