On Tue, Oct 09, 2012 at 14:08:18, Andrey Mandychev wrote:
> Hi,
>
> Please find below some additional comments.
>
> Actually it's not a real issue. It's more warning than issue. When you
> are trying to delete element from the queue the implementation of
> list_del (in list_debug.c) checks that previous element and next element
> of the element you are going to delete reference to this element
> properly. In other words the method checks the integrity of the queue
> before deleting the element and it generates warning if something is
> wrong. In my case the head looses a pointer to the next element because
> of INIT_LIST_HEAD()
> and when we try to delete this element from the
> queue the list_del() generates warning because the previous element
> (i.e. head) doesn't reference to this element (element we want to
> delete).
>
> void __list_del_entry(struct list_head *entry)
> {
> struct list_head *prev, *next;
>
> prev = entry->prev;
> next = entry->next;
>
> if (WARN(next == LIST_POISON1,
> "list_del corruption, %p->next is LIST_POISON1 (%p)\n",
> entry, LIST_POISON1) ||
> WARN(prev == LIST_POISON2,
> "list_del corruption, %p->prev is LIST_POISON2 (%p)\n",
> entry, LIST_POISON2) ||
> WARN(prev->next != entry,
> "list_del corruption. prev->next should be %p, "
> "but was %p\n", entry, prev->next) ||
> WARN(next->prev != entry,
> "list_del corruption. next->prev should be %p, "
> "but was %p\n", entry, next->prev))
> return;
>
> __list_del(prev, next);
> }
>
> So my patch is a small improvement that avoids generating this kind of
> warning.
>
Any mechanism or suggestion to reproduce this issue, which I can
use to reproduce this issue. Just switching between LCD<=>TV, will be enough
to hit this issue?
Thanks,
Vaibhav
> --
> BR,
> Andrei
>
>
> On Mon, Oct 8, 2012 at 4:50 PM, Hiremath, Vaibhav <hvaibhav@xxxxxx>
> wrote:
>
>
> On Fri, Oct 05, 2012 at 21:14:25, Andrei Mandychev wrote:
> > If there is a buffer with VIDEOBUF_QUEUED state it won't be
> deleted properly
> > because the head of queue loses its elements by calling
> INIT_LIST_HEAD()
> > before videobuf_streamoff().
>
>
> "dma_queue" is driver internal queue and videobuf_streamoff()
> function
> will end up into buf_release() callback, which in our case
> doesn't do
> anything with dmaqueue.
>
>
> Did you face any runtime issues with this? I still did not
> understand
> about this corruption thing.
>
> Thanks,
> Vaibhav
>
> > ---
> > drivers/media/video/omap/omap_vout.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/video/omap/omap_vout.c
> b/drivers/media/video/omap/omap_vout.c
> > index 409da0f..f02eb8e 100644
> > --- a/drivers/media/video/omap/omap_vout.c
> > +++ b/drivers/media/video/omap/omap_vout.c
> > @@ -1738,8 +1738,8 @@ static int vidioc_streamoff(struct file
> *file, void *fh, enum v4l2_buf_type i)
> > v4l2_err(&vout->vid_dev->v4l2_dev, "failed to
> change mode in"
> > " streamoff\n");
> >
> > - INIT_LIST_HEAD(&vout->dma_queue);
> > ret = videobuf_streamoff(&vout->vbq);
> > + INIT_LIST_HEAD(&vout->dma_queue);
> >
> > return ret;
> > }
> > --
> > 1.7.9.5
> >
> >
>
>
>
>
>
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