Re: [PATCHv2 5/8] [media] pvrusb2: initialize standards mask before detecting standard

[Mike Isely <isely@xxxxxxxxx>]

On Wed, 5 Oct 2011, Mauro Carvalho Chehab wrote:

> Em 05-10-2011 11:00, Mike Isely escreveu:
> > 
> > Mauro:
> > 
> > With the line you've just added, then the " = arg" assignment in the
> > immediate prior line is effectively dead code.  Try this instead:
> 
> Look better:
> 
> > >   		v4l2_std_id *std = arg;
> > > +		*std = V4L2_STD_ALL;
> 
> The above code is creating a pointer 'std' of the type 'v4l2_std_id', and
> initializing the pointer with the void *arg.

Oh yeah, you're absolutely right.  I got visually tricked by the well 
known confusing C initialization syntax when dealing with pointers!  
I've got to not respond to stuff like this in the morning until I've 
finished waking up.  Duh...

> 
> Then, it is doing an indirect reference to the pointer, filling its
> contents with V4L2_STD_ALL value.
> 
> The code above is sane (and, btw, it works). After those patches, the
> detection code will detect PAL/M or NTSC/M depending on the channel I
> tune here (my cable operator broadcasts some channels with one format,
> and others with the other one). Before this patch and the msp3400, it
> would return a mask with PAL/M and PAL/60 or a mask with all NTSC/M formats.

Regarding your first version of the patch:

Acked-By: Mike Isely <isely@xxxxxxxxx>

  -Mike

> 
> Regards,
> Mauro.
> 
> > 
> >   	case VIDIOC_QUERYSTD:
> >   	{
> > -		v4l2_std_id *std = arg;
> > +		v4l2_std_id *std = V4L2_STD_ALL;
> >   		ret = pvr2_hdw_get_detected_std(hdw, std);
> >   		break;
> >   	}
> > 
> >    -Mike
> > 
> > 
> > On Tue, 4 Oct 2011, Mauro Carvalho Chehab wrote:
> > 
> > > Signed-off-by: Mauro Carvalho Chehab<mchehab@xxxxxxxxxx>
> > > ---
> > >   drivers/media/video/pvrusb2/pvrusb2-v4l2.c |    1 +
> > >   1 files changed, 1 insertions(+), 0 deletions(-)
> > > 
> > > diff --git a/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
> > > b/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
> > > index 0d029da..ce7ac45 100644
> > > --- a/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
> > > +++ b/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
> > > @@ -230,6 +230,7 @@ static long pvr2_v4l2_do_ioctl(struct file *file,
> > > unsigned int cmd, void *arg)
> > >   	case VIDIOC_QUERYSTD:
> > >   	{
> > >   		v4l2_std_id *std = arg;
> > > +		*std = V4L2_STD_ALL;
> > >   		ret = pvr2_hdw_get_detected_std(hdw, std);
> > >   		break;
> > >   	}
> > > 
> > 
> 
> 

-- 

Mike Isely
isely @ isely (dot) net
PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8
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