[media] uvcvideo: Delay initialization of XU controls

XU controls initialization requires querying the device for control
information. As some buggy UVC devices will crash when queried
repeatedly in a tight loop, delay XU controls initialization until first
use.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 107 insertions, 87 deletions

diff --git a/drivers/media/video/uvc/uvc_ctrl.c b/drivers/media/video/uvc/uvc_ctrl.c
index 97a2395671b5..a0c9d580ca9d 100644
--- a/drivers/media/video/uvc/uvc_ctrl.c
+++ b/drivers/media/video/uvc/uvc_ctrl.c
@@ -1164,6 +1164,90 @@ int uvc_ctrl_set(struct uvc_video_chain *chain,
  * Dynamic controls
  */
 
+/*
+ * Query control information (size and flags) for XU controls.
+ */
+static int uvc_ctrl_fill_xu_info(struct uvc_device *dev,
+        const struct uvc_control *ctrl, struct uvc_control_info *info)
+{
+        u8 *data;
+        int ret;
+
+        data = kmalloc(2, GFP_KERNEL);
+        if (data == NULL)
+                return -ENOMEM;
+
+        memcpy(info->entity, ctrl->entity->extension.guidExtensionCode,
+               sizeof(info->entity));
+        info->index = ctrl->index;
+        info->selector = ctrl->index + 1;
+
+        /* Query and verify the control length (GET_LEN) */
+        ret = uvc_query_ctrl(dev, UVC_GET_LEN, ctrl->entity->id, dev->intfnum,
+                             info->selector, data, 2);
+        if (ret < 0) {
+                uvc_trace(UVC_TRACE_CONTROL,
+                          "GET_LEN failed on control %pUl/%u (%d).\n",
+                           info->entity, info->selector, ret);
+                goto done;
+        }
+
+        info->size = le16_to_cpup((__le16 *)data);
+
+        /* Query the control information (GET_INFO) */
+        ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id, dev->intfnum,
+                             info->selector, data, 1);
+        if (ret < 0) {
+                uvc_trace(UVC_TRACE_CONTROL,
+                          "GET_INFO failed on control %pUl/%u (%d).\n",
+                          info->entity, info->selector, ret);
+                goto done;
+        }
+
+        info->flags = UVC_CONTROL_GET_MIN | UVC_CONTROL_GET_MAX
+                    | UVC_CONTROL_GET_RES | UVC_CONTROL_GET_DEF
+                    | (data[0] & UVC_CONTROL_CAP_GET ? UVC_CONTROL_GET_CUR : 0)
+                    | (data[0] & UVC_CONTROL_CAP_SET ? UVC_CONTROL_SET_CUR : 0)
+                    | (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
+                       UVC_CONTROL_AUTO_UPDATE : 0);
+
+        uvc_trace(UVC_TRACE_CONTROL, "XU control %pUl/%u queried: len %u, "
+                  "flags { get %u set %u auto %u }.\n",
+                  info->entity, info->selector, info->size,
+                  (info->flags & UVC_CONTROL_GET_CUR) ? 1 : 0,
+                  (info->flags & UVC_CONTROL_SET_CUR) ? 1 : 0,
+                  (info->flags & UVC_CONTROL_AUTO_UPDATE) ? 1 : 0);
+
+done:
+        kfree(data);
+        return ret;
+}
+
+static int uvc_ctrl_add_info(struct uvc_device *dev, struct uvc_control *ctrl,
+        const struct uvc_control_info *info);
+
+static int uvc_ctrl_init_xu_ctrl(struct uvc_device *dev,
+        struct uvc_control *ctrl)
+{
+        struct uvc_control_info info;
+        int ret;
+
+        if (ctrl->initialized)
+                return 0;
+
+        ret = uvc_ctrl_fill_xu_info(dev, ctrl, &info);
+        if (ret < 0)
+                return ret;
+
+        ret = uvc_ctrl_add_info(dev, ctrl, &info);
+        if (ret < 0)
+                uvc_trace(UVC_TRACE_CONTROL, "Failed to initialize control "
+                          "%pUl/%u on device %s entity %u\n", info.entity,
+                          info.selector, dev->udev->devpath, ctrl->entity->id);
+
+        return ret;
+}
+
 int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
         struct uvc_xu_control *xctrl, int set)
 {
@@ -1186,13 +1270,10 @@ int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
                 return -EINVAL;
         }
 
-        /* Find the control. */
+        /* Find the control and perform delayed initialization if needed. */
         for (i = 0; i < entity->ncontrols; ++i) {
                 ctrl = &entity->controls[i];
-                if (!ctrl->initialized)
-                        continue;
-
-                if (ctrl->info.selector == xctrl->selector) {
+                if (ctrl->index == xctrl->selector - 1) {
                         found = 1;
                         break;
                 }
@@ -1204,6 +1285,10 @@ int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
                 return -EINVAL;
         }
 
+        ret = uvc_ctrl_init_xu_ctrl(chain->dev, ctrl);
+        if (ret < 0)
+                return -ENOENT;
+
         /* Validate control data size. */
         if (ctrl->info.size != xctrl->size)
                 return -EINVAL;
@@ -1295,65 +1380,6 @@ int uvc_ctrl_resume_device(struct uvc_device *dev)
  */
 
 /*
- * Query control information (size and flags) for XU controls.
- */
-static int uvc_ctrl_fill_xu_info(struct uvc_device *dev,
-        const struct uvc_control *ctrl, struct uvc_control_info *info)
-{
-        u8 *data;
-        int ret;
-
-        data = kmalloc(2, GFP_KERNEL);
-        if (data == NULL)
-                return -ENOMEM;
-
-        memcpy(info->entity, ctrl->entity->extension.guidExtensionCode,
-               sizeof(info->entity));
-        info->index = ctrl->index;
-        info->selector = ctrl->index + 1;
-
-        /* Query and verify the control length (GET_LEN) */
-        ret = uvc_query_ctrl(dev, UVC_GET_LEN, ctrl->entity->id, dev->intfnum,
-                             info->selector, data, 2);
-        if (ret < 0) {
-                uvc_trace(UVC_TRACE_CONTROL,
-                          "GET_LEN failed on control %pUl/%u (%d).\n",
-                           info->entity, info->selector, ret);
-                goto done;
-        }
-
-        info->size = le16_to_cpup((__le16 *)data);
-
-        /* Query the control information (GET_INFO) */
-        ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id, dev->intfnum,
-                             info->selector, data, 1);
-        if (ret < 0) {
-                uvc_trace(UVC_TRACE_CONTROL,
-                          "GET_INFO failed on control %pUl/%u (%d).\n",
-                          info->entity, info->selector, ret);
-                goto done;
-        }
-
-        info->flags = UVC_CONTROL_GET_MIN | UVC_CONTROL_GET_MAX
-                    | UVC_CONTROL_GET_RES | UVC_CONTROL_GET_DEF
-                    | (data[0] & UVC_CONTROL_CAP_GET ? UVC_CONTROL_GET_CUR : 0)
-                    | (data[0] & UVC_CONTROL_CAP_SET ? UVC_CONTROL_SET_CUR : 0)
-                    | (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
-                       UVC_CONTROL_AUTO_UPDATE : 0);
-
-        uvc_trace(UVC_TRACE_CONTROL, "XU control %pUl/%u queried: len %u, "
-                  "flags { get %u set %u auto %u }.\n",
-                  info->entity, info->selector, info->size,
-                  (info->flags & UVC_CONTROL_GET_CUR) ? 1 : 0,
-                  (info->flags & UVC_CONTROL_SET_CUR) ? 1 : 0,
-                  (info->flags & UVC_CONTROL_AUTO_UPDATE) ? 1 : 0);
-
-done:
-        kfree(data);
-        return ret;
-}
-
-/*
  * Add control information to a given control.
  */
 static int uvc_ctrl_add_info(struct uvc_device *dev, struct uvc_control *ctrl,
@@ -1434,7 +1460,7 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
 
         if (mapping->id & ~V4L2_CTRL_ID_MASK) {
                 uvc_trace(UVC_TRACE_CONTROL, "Can't add mapping '%s', control "
-                        "control id 0x%08x is invalid.\n", mapping->name,
+                        "id 0x%08x is invalid.\n", mapping->name,
                         mapping->id);
                 return -EINVAL;
         }
@@ -1443,13 +1469,13 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
         list_for_each_entry(entity, &dev->entities, list) {
                 unsigned int i;
 
-                if (!uvc_entity_match_guid(entity, mapping->entity))
+                if (UVC_ENTITY_TYPE(entity) != UVC_VC_EXTENSION_UNIT ||
+                    !uvc_entity_match_guid(entity, mapping->entity))
                         continue;
 
                 for (i = 0; i < entity->ncontrols; ++i) {
                         ctrl = &entity->controls[i];
-                        if (ctrl->initialized &&
-                            ctrl->info.selector == mapping->selector) {
+                        if (ctrl->index == mapping->selector - 1) {
                                 found = 1;
                                 break;
                         }
@@ -1464,6 +1490,13 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
         if (mutex_lock_interruptible(&chain->ctrl_mutex))
                 return -ERESTARTSYS;
 
+        /* Perform delayed initialization of XU controls */
+        ret = uvc_ctrl_init_xu_ctrl(dev, ctrl);
+        if (ret < 0) {
+                ret = -ENOENT;
+                goto done;
+        }
+
         list_for_each_entry(map, &ctrl->info.mappings, list) {
                 if (mapping->id == map->id) {
                         uvc_trace(UVC_TRACE_CONTROL, "Can't add mapping '%s', "
@@ -1567,26 +1600,13 @@ static void uvc_ctrl_init_ctrl(struct uvc_device *dev, struct uvc_control *ctrl)
         const struct uvc_control_mapping *mend =
                 mapping + ARRAY_SIZE(uvc_ctrl_mappings);
 
-        /* Query XU controls for control information */
-        if (UVC_ENTITY_TYPE(ctrl->entity) == UVC_VC_EXTENSION_UNIT) {
-                struct uvc_control_info info;
-                int ret;
-
-                ret = uvc_ctrl_fill_xu_info(dev, ctrl, &info);
-                if (ret < 0)
-                        return;
-
-                ret = uvc_ctrl_add_info(dev, ctrl, &info);
-                if (ret < 0) {
-                        /* Skip the control */
-                        uvc_trace(UVC_TRACE_CONTROL, "Failed to initialize "
-                                "control %pUl/%u on device %s entity %u\n",
-                                info.entity, info.selector, dev->udev->devpath,
-                                ctrl->entity->id);
-                        memset(ctrl, 0, sizeof(*ctrl));
-                }
+        /* XU controls initialization requires querying the device for control
+         * information. As some buggy UVC devices will crash when queried
+         * repeatedly in a tight loop, delay XU controls initialization until
+         * first use.
+         */
+        if (UVC_ENTITY_TYPE(ctrl->entity) == UVC_VC_EXTENSION_UNIT)
                 return;
-        }
 
         for (; info < iend; ++info) {
                 if (uvc_entity_match_guid(ctrl->entity, info->entity) &&