Am Montag, den 18.05.2009, 11:53 +0800 schrieb figo.zhang:
> On Mon, 2009-05-18 at 05:07 +0200, hermann pitton wrote:
> > Am Montag, den 18.05.2009, 10:13 +0800 schrieb figo.zhang:
> > > saa7134-video.c: poll method lose race condition
> > >
> > >
> > > Signed-off-by: Figo.zhang <figo.zhang@xxxxxxxxxxxxx>
> > > ---
> > > drivers/media/video/saa7134/saa7134-video.c | 9 ++++++---
> > > 1 files changed, 6 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/media/video/saa7134/saa7134-video.c b/drivers/media/video/saa7134/saa7134-video.c
> > > index 493cad9..95733df 100644
> > > --- a/drivers/media/video/saa7134/saa7134-video.c
> > > +++ b/drivers/media/video/saa7134/saa7134-video.c
> > > @@ -1423,11 +1423,13 @@ video_poll(struct file *file, struct poll_table_struct *wait)
> > > {
> > > struct saa7134_fh *fh = file->private_data;
> > > struct videobuf_buffer *buf = NULL;
> > > + unsigned int rc = 0;
> > >
> > > if (V4L2_BUF_TYPE_VBI_CAPTURE == fh->type)
> > > return videobuf_poll_stream(file, &fh->vbi, wait);
> > >
> > > if (res_check(fh,RESOURCE_VIDEO)) {
> > > + mutex_lock(&fh->cap.vb_lock);
> > > if (!list_empty(&fh->cap.stream))
> > > buf = list_entry(fh->cap.stream.next, struct videobuf_buffer, stream);
> > > } else {
> > > @@ -1446,13 +1448,14 @@ video_poll(struct file *file, struct poll_table_struct *wait)
> > > }
> > >
> > > if (!buf)
> > > - return POLLERR;
> > > + rc = POLLERR;
> > >
> > > poll_wait(file, &buf->done, wait);
> > > if (buf->state == VIDEOBUF_DONE ||
> > > buf->state == VIDEOBUF_ERROR)
> > > - return POLLIN|POLLRDNORM;
> > > - return 0;
> > > + rc = POLLIN|POLLRDNORM;
> > > + mutex_unlock(&fh->cap.vb_lock);
> > > + return rc;
> > >
> > > err:
> > > mutex_unlock(&fh->cap.vb_lock);
> > >
> > >
> >
> > Can you please give some description on what your patch might do
> > something?
> >
> > Or are you a robot?
> >
> > Then, please give us your serial number, production year, and when we
> > can expect you are out of duty and replaced ;)
> >
> > Cheers,
> > Hermann
> >
> >
> >
>
> hi, I just using the saa7134 chip to do a video capture card. The
> saa7134 driver in linux kernel, i found that the poll method have lose
> race condition for "RESOURCE_VIDEO". It have better to add a mutex lock.
>
OK then, but better stay away from the core files.
On what kernel this is?
Give us some copy/paste "dmesg" output for your card with "i2c_scan=1".
Don't lose tuner stuff on this.
Thanks,
Hermann
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