Don't handle the first output terminal in a chain in a special way. Use
uvc_scan_chain_entity() like for all other entities, making the chain
scan code more generic.
Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Index: v4l-dvb-mc/linux/drivers/media/video/uvc/uvc_driver.c
===================================================================
--- v4l-dvb-mc.orig/linux/drivers/media/video/uvc/uvc_driver.c
+++ v4l-dvb-mc/linux/drivers/media/video/uvc/uvc_driver.c
@@ -1256,13 +1256,12 @@ static int uvc_scan_chain_entity(struct
break;
case UVC_TT_STREAMING:
- if (uvc_trace_param & UVC_TRACE_PROBE)
- printk(" <- IT %d\n", entity->id);
-
- if (!UVC_ENTITY_IS_ITERM(entity)) {
- uvc_trace(UVC_TRACE_DESCR, "Unsupported input "
- "terminal %u.\n", entity->id);
- return -1;
+ if (UVC_ENTITY_IS_ITERM(entity)) {
+ if (uvc_trace_param & UVC_TRACE_PROBE)
+ printk(" <- IT %d\n", entity->id);
+ } else {
+ if (uvc_trace_param & UVC_TRACE_PROBE)
+ printk(" OT %d", entity->id);
}
break;
@@ -1342,10 +1341,11 @@ static int uvc_scan_chain_forward(struct
}
static int uvc_scan_chain_backward(struct uvc_video_chain *chain,
- struct uvc_entity *entity)
+ struct uvc_entity **_entity)
{
+ struct uvc_entity *entity = *_entity;
struct uvc_entity *term;
- int id = -1, i;
+ int id = -EINVAL, i;
switch (UVC_ENTITY_TYPE(entity)) {
case UVC_VC_EXTENSION_UNIT:
@@ -1389,34 +1389,49 @@ static int uvc_scan_chain_backward(struc
id = 0;
break;
+
+ case UVC_ITT_VENDOR_SPECIFIC:
+ case UVC_ITT_CAMERA:
+ case UVC_ITT_MEDIA_TRANSPORT_INPUT:
+ case UVC_OTT_VENDOR_SPECIFIC:
+ case UVC_OTT_DISPLAY:
+ case UVC_OTT_MEDIA_TRANSPORT_OUTPUT:
+ case UVC_TT_STREAMING:
+ id = UVC_ENTITY_IS_OTERM(entity) ? entity->output.bSourceID : 0;
+ break;
+ }
+
+ if (id <= 0) {
+ *_entity = NULL;
+ return id;
+ }
+
+ entity = uvc_entity_by_id(chain->dev, id);
+ if (entity == NULL) {
+ uvc_trace(UVC_TRACE_DESCR, "Found reference to "
+ "unknown entity %d.\n", id);
+ return -EINVAL;
}
- return id;
+ *_entity = entity;
+ return 0;
}
static int uvc_scan_chain(struct uvc_video_chain *chain,
- struct uvc_entity *oterm)
+ struct uvc_entity *term)
{
struct uvc_entity *entity, *prev;
- int id;
- entity = oterm;
- list_add_tail(&entity->chain, &chain->entities);
- uvc_trace(UVC_TRACE_PROBE, "Scanning UVC chain: OT %d", entity->id);
+ uvc_trace(UVC_TRACE_PROBE, "Scanning UVC chain:");
- id = entity->output.bSourceID;
- while (id != 0) {
- prev = entity;
- entity = uvc_entity_by_id(chain->dev, id);
- if (entity == NULL) {
- uvc_trace(UVC_TRACE_DESCR, "Found reference to "
- "unknown entity %d.\n", id);
- return -EINVAL;
- }
+ entity = term;
+ prev = NULL;
+ while (entity != NULL) {
+ /* Entity must not be part of an existing chain */
if (entity->chain.next || entity->chain.prev) {
uvc_trace(UVC_TRACE_DESCR, "Found reference to "
- "entity %d already in chain.\n", id);
+ "entity %d already in chain.\n", entity->id);
return -EINVAL;
}
@@ -1428,14 +1443,10 @@ static int uvc_scan_chain(struct uvc_vid
if (uvc_scan_chain_forward(chain, entity, prev) < 0)
return -EINVAL;
- /* Stop when a terminal is found. */
- if (UVC_ENTITY_IS_TERM(entity))
- break;
-
/* Backward scan */
- id = uvc_scan_chain_backward(chain, entity);
- if (id < 0)
- return id;
+ prev = entity;
+ if (uvc_scan_chain_backward(chain, &entity) < 0)
+ return -EINVAL;
}
return 0;
--
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