Re: [PATCH v2] media: s5p-mfc: Add support for V4L2_MEMORY_DMABUF type

[Mauro Carvalho Chehab <mchehab+samsung@kernel.org>]

Em Mon, 18 Dec 2017 09:19:11 +0100
Marek Szyprowski <m.szyprowski@samsung.com> escreveu:

> Hi Hans,
> 
> On 2017-12-15 16:57, Hans Verkuil wrote:
> > On 14/12/17 15:11, Marek Szyprowski wrote:  
> >> I would like to get your opinion on this patch. Do you think it makes sense to:
> >>
> >> 1. add limited support for USERPTR and DMA-buf import? (limited means driver will accept setting buffer pointer/fd only once after reqbufs for each buffer index)  
> > I don't like this. It's unexpected almost-but-not-quite behavior that will make
> > life very difficult for userspace.
> >  
> >> 2. add a V4L2 device flag to let userspace to discover if device support queue buffer reconfiguration on-fly or not?  
> > This seems to me a better approach. It should be possible to implement most/all of this
> > in vb2, but we need to find a way to signal this to the user.  
> 
> Okay, I will prepare a patch with such flag soon.
> 
> > Is this an MFC limitation for the decoder, encoder or both? And is it a limitation
> > of the capture or output side or both?  
> 
> Both and both. DMA addresses of all buffers must be known while 
> initializing decoder
> and encoder.
> 
>  > ...  
> 
> Best regards

Marek/Sylwester,

What's the status of this one? The patch still applies (with a minor
conflict).

Thanks,
Mauro