Hi Stephan,
On Wednesday 22 June 2011 00:55:36 Laurent Pinchart wrote:
> On Wednesday 01 June 2011 00:24:21 Stephan Lachowsky wrote:
> > The search for matching extension units fails to take account of the
> > current chain. In the case where you have two distinct video chains,
> > both containing an XU with the same GUID but different unit ids, you
> > will be unable to perform a mapping on the second chain because entity
> > on the first chain will always be found first
> >
> > Fix this by only searching the current chain when performing a control
> > mapping. This is analogous to the search used by uvc_find_control(),
> > and is the correct behaviour.
>
> Thanks for the patch. I agree with your analysis, but I'm concerned about
> devices that might have extension units not connected to any chain. They
> would become unaccessible.
>
> Devices for which extension unit control mappings have been published have
> all their XUs connected to a chain, so I'm OK with the patch. I will add a
> TODO comment to remind me of the issue, and I'll solve the problem later
> if it ever occurs.
Sorry, I spoke too fast. uvc_find_control() has the same issue, so there's no
need to add a comment specific to uvc_ctrl_add_mapping(). I'll apply your
patch as-is.
> > Signed-off-by: Stephan Lachowsky <stephan.lachowsky@xxxxxxxxxxxx>
> > ---
> >
> > drivers/media/video/uvc/uvc_ctrl.c | 4 ++--
> > 1 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/video/uvc/uvc_ctrl.c
> > b/drivers/media/video/uvc/uvc_ctrl.c index 59f8a9a..a77648f 100644
> > --- a/drivers/media/video/uvc/uvc_ctrl.c
> > +++ b/drivers/media/video/uvc/uvc_ctrl.c
> > @@ -1565,8 +1565,8 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain
> > *chain, return -EINVAL;
> >
> > }
> >
> > - /* Search for the matching (GUID/CS) control in the given device */
> > - list_for_each_entry(entity, &dev->entities, list) {
> > + /* Search for the matching (GUID/CS) control on the current chain */
> > + list_for_each_entry(entity, &chain->entities, chain) {
> >
> > unsigned int i;
> >
> > if (UVC_ENTITY_TYPE(entity) != UVC_VC_EXTENSION_UNIT ||
--
Regards,
Laurent Pinchart
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