On Mon, 2009-05-18 at 05:49 +0200, hermann pitton wrote:
> 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.zh...@kolorific.com>
> > > > --- 
> > > > 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
> 
> 
> 
hi, hermann pitton ,i am using the git-kernel, the card have some
hardware problems now.

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