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path: root/drivers/media/usb/uvc/uvc_driver.c
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Diffstat (limited to 'drivers/media/usb/uvc/uvc_driver.c')
-rw-r--r--drivers/media/usb/uvc/uvc_driver.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 30ef2a3110f7..9a791d8ef200 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -1712,10 +1712,35 @@ static int uvc_scan_chain_forward(struct uvc_video_chain *chain,
if (forward->bNrInPins != 1) {
uvc_dbg(chain->dev, DESCR,
"Extension unit %d has more than 1 input pin\n",
- entity->id);
+ forward->id);
return -EINVAL;
}
+ /*
+ * Some devices reference an output terminal as the
+ * source of extension units. This is incorrect, as
+ * output terminals only have an input pin, and thus
+ * can't be connected to any entity in the forward
+ * direction. The resulting topology would cause issues
+ * when registering the media controller graph. To
+ * avoid this problem, connect the extension unit to
+ * the source of the output terminal instead.
+ */
+ if (UVC_ENTITY_IS_OTERM(entity)) {
+ struct uvc_entity *source;
+
+ source = uvc_entity_by_id(chain->dev,
+ entity->baSourceID[0]);
+ if (!source) {
+ uvc_dbg(chain->dev, DESCR,
+ "Can't connect extension unit %u in chain\n",
+ forward->id);
+ break;
+ }
+
+ forward->baSourceID[0] = source->id;
+ }
+
list_add_tail(&forward->chain, &chain->entities);
if (!found)
uvc_dbg_cont(PROBE, " (->");
@@ -1735,6 +1760,13 @@ static int uvc_scan_chain_forward(struct uvc_video_chain *chain,
return -EINVAL;
}
+ if (UVC_ENTITY_IS_OTERM(entity)) {
+ uvc_dbg(chain->dev, DESCR,
+ "Unsupported connection between output terminals %u and %u\n",
+ entity->id, forward->id);
+ break;
+ }
+
list_add_tail(&forward->chain, &chain->entities);
if (!found)
uvc_dbg_cont(PROBE, " (->");