[libcamera-devel] [PATCH v3] MediaLink: Make MediaLink::setEnabled account for existing

[Daniel Scally]

Hi Laurent,

No objections from me

Dan

On Fri, 28 Aug 2020, 17:53 Laurent Pinchart, <
laurent.pinchart at ideasonboard.com> wrote:

> On Fri, Aug 28, 2020 at 10:40:45AM +0100, Kieran Bingham wrote:
> > Hi Dan,
> >
> > Thankyou, and yes - this git-send-mail version applies perfectly well
> > with git-am.
> >
> > On 28/08/2020 07:25, Dan Scally wrote:
> > > The setupLink function fails (ioctl returns EINVAL) when it passes the
> > > MEDIA_LNK_FL_ENABLE flag to a link that is already flagged with
> > > MEDIA_LNK_FL_ENABLE and MEDIA_LNK_FL_IMMUTABLE. Contrast to media-ctl's
> > > equivalent media_setup_link() which ORs the new flags with the existing
> > > values. This patch modifies the behaviour of setupLink() to behave the
> > > same as media_setup_link() in media-ctl.
>
> The commit message is now out of date I'm afraid, as the patch doesn't
> modify setupLink() anymore. No worries, I'll update this to
>
> The MediaDevice::setupLink() function fails (ioctl returns EINVAL) when
> it passes only the MEDIA_LNK_FL_ENABLE flag to a link that is already
> flagged with MEDIA_LNK_FL_ENABLE and MEDIA_LNK_FL_IMMUTABLE. Contrast to
> media-ctl's equivalent media_setup_link() which ORs the new flags with
> the existing values. Fix this by preserving all flags but
> MEDIA_LNK_FL_ENABLED in MediaLink::setEnabled().
>
> The subject line seems to also have been truncated, I think it misses
> "flags" at the end. It also should start with "libcamera: media_object:"
> to match the usual style of commit messages.
>
> Please let me know if you have any objection.
>
> > >
> > > Signed-off-by: Dan Scally <djrscally at gmail.com>
> > > ---
> > >
> > > Changelog:
> > >
> > >     v3 - Moved the change to MediaLink::setEnabled()
> > >
> > >     v2 - Simplified by removing the call to link() to fetch a link
> that's
> > >             already passed as a parameter to the function.
> > >
> > >  src/libcamera/media_object.cpp | 3 ++-
> > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/src/libcamera/media_object.cpp
> b/src/libcamera/media_object.cpp
> > > index ce77a72..a2e6a0d 100644
> > > --- a/src/libcamera/media_object.cpp
> > > +++ b/src/libcamera/media_object.cpp
> > > @@ -115,7 +115,8 @@ LOG_DECLARE_CATEGORY(MediaDevice)
> > >   */
> > >  int MediaLink::setEnabled(bool enable)
> > >  {
> > > -   unsigned int flags = enable ? MEDIA_LNK_FL_ENABLED : 0;
> > > +   unsigned int flags = (flags_ & ~MEDIA_LNK_FL_ENABLED)
> > > +                                           | (enable ?
> MEDIA_LNK_FL_ENABLED : 0);
> >
> > To fit our coding style, that second line should be aligned so that the
> > | operator is below the = operator I think ... but that's really minor
> > and is easily handled when applying.
> >
> > Other than that, this sounds like a better approach that v2 indeed,
> > especially as now the flags_ is going to be kept consistent.
> >
> > Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
>
> With this addressed,
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>
> > >
> > >     int ret = dev_->setupLink(this, flags);
> > >     if (ret)
> > >
>
> --
> Regards,
>
> Laurent Pinchart
>
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