Re: [PATCH 0 of 9] videobuf fixes

[Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxx>]

On Mon, 31 Mar 2008 20:11:30 -0700
Brandon Philips <brandon@xxxxxxxx> wrote:

> On 18:31 Mon 31 Mar 2008, Mauro Carvalho Chehab wrote:
> > > > The patch is wrong. 
> > > 
> > > The patch fixes the unsafe way vivi is doing multiple opens right now
> > > and I am uninterested in spending anymore time trying to fix up vivi
> > > right now.  If you could fix vivi up that would be great.  
> > 
> > If the issue is specific to to vivi, that's ok. I'm just wandering if the
> > changesets would break a driver for a real device.
> > 
> > Unfortunately, I couldn't test your patch on a real hardware. The hardware I use
> > here to test PCI boards is currently broken[1].
> 
> I have tested my series on saa7134 hardware and it went OK.  Although,
> having someone else play with my patchset would be nice :)

Have you tested to run ffmpeg or mencoder under /dev/video0, while listening to
something using mmap()? The errors I got with vivi seems to occur if I do something like:

App A starts streaming;
App B starts streaming;
Stop A app -> OOPS

I didn't got error with this sequence:

App A starts streaming;
App B starts streaming;
Stop B;
Stop A.

> > > > 	2) you can see a program with an userspace app and record the
> > > > 	stream with another app. Both xawtv and xdtv do this, when you
> > > > 	ask for record: They call mencoder, asking it to read from
> > > > 	/dev/video0. This way, you'll have the tv app reading, using
> > > > 	mmap() or overlay methods, while mencoder is calling read() to
> > > > 	receive the stream.
> > > 
> > > Yes, I know.  But, vivi has no permission control mechanism right now
> > > for differentiating between streaming file handles and control ones.
> > 
> > What the other drivers do is to implement a small code for this lock. You may
> > take a look on res_get(), for example, on cx88. 
> 
> Yes, I know.  But, I don't don't have time to fix vivi up all the way.

Ok. Could you please update your tree with the latest patches? I think the
better way is to merge they on v4l/dvb and ask more people to test.

Cheers,
Mauro

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