Only standard controls can be successfully cloned: handler_new_ref, used by v4l2_ctrl_request_clone(), forcibly calls v4l2_ctrl_new_std() which fails to find custom controls names, and we eventually hit the condition that name == NULL in v4l2_ctrl_new().
This prevents us from using non-standard controls with requests, but that is enough for testing purposes. Signed-off-by: Alexandre Courbot <acour...@chromium.org> --- drivers/media/v4l2-core/v4l2-ctrls.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c index 166647817efb..7a81aa5959c3 100644 --- a/drivers/media/v4l2-core/v4l2-ctrls.c +++ b/drivers/media/v4l2-core/v4l2-ctrls.c @@ -2772,6 +2772,11 @@ int v4l2_ctrl_request_clone(struct v4l2_ctrl_handler *hdl, if (filter && !filter(ctrl)) continue; err = handler_new_ref(hdl, ctrl, &new_ref, false); + if (err) { + printk("%s: handler_new_ref on control %x (%s) returned %d\n", __func__, ctrl->id, ctrl->name, err); + err = 0; + continue; + } if (err) break; if (from->is_request) -- 2.16.1.291.g4437f3f132-goog