qv4l2: control handling fixes

1) Don't attempt to read write-only controls
2) Set default string value to the proper minimum length (>= 0) containing spaces.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

diff --git a/utils/qv4l2/ctrl-tab.cpp b/utils/qv4l2/ctrl-tab.cpp
index 7503a65..79c3f9f 100644 (file)
--- a/utils/qv4l2/ctrl-tab.cpp
+++ b/utils/qv4l2/ctrl-tab.cpp
@@ -514,14 +514,17 @@ void ApplicationWindow::refresh(unsigned ctrl_class)
        if (!m_haveExtendedUserCtrls && ctrl_class == V4L2_CTRL_CLASS_USER) {
                for (unsigned i = 0; i < m_classMap[ctrl_class].size(); i++) {
                        unsigned id = m_classMap[ctrl_class][i];
-
                        v4l2_control c;
 
+                       queryctrl(m_ctrlMap[id]);
+                       if (m_ctrlMap[id].type == V4L2_CTRL_TYPE_BUTTON)
+                               continue;
+                       if (m_ctrlMap[id].flags & V4L2_CTRL_FLAG_WRITE_ONLY)
+                               continue;
                        c.id = id;
                        if (ioctl(VIDIOC_G_CTRL, &c)) {
                                errorCtrl(id, errno);
                        }
-                       queryctrl(m_ctrlMap[id]);
                        setVal(id, c.value);
                        m_widgetMap[id]->setDisabled(m_ctrlMap[id].flags & CTRL_FLAG_DISABLED);
                }
@@ -729,7 +732,7 @@ void ApplicationWindow::setDefaults(unsigned ctrl_class)
                if (m_ctrlMap[id].type == V4L2_CTRL_TYPE_INTEGER64)
                        setVal64(id, 0);
                else if (m_ctrlMap[id].type == V4L2_CTRL_TYPE_STRING)
-                       setString(id, "");
+                       setString(id, QString(' ', m_ctrlMap[id].minimum));
                else if (m_ctrlMap[id].type != V4L2_CTRL_TYPE_BUTTON)
                        setVal(id, m_ctrlMap[id].default_value);
        }