[PATCHv2 3/9] v4l: add buffer exporting via dmabuf

[Rob Clark]

On Tue, Jul 31, 2012 at 7:11 AM, Hans Verkuil <hverkuil at xs4all.nl> wrote:
>> > For that matter, wouldn't it be useful to support exporting a userptr buffer
>> > at some point in the future?
>>
>> Shouldn't USERPTR usage be discouraged once we get dma-buf support ?
>
> Why? It's perfectly fine to use it and it's not going away.
>
> I'm not saying that we should support exporting a userptr buffer as a dmabuf fd,
> but I'm just wondering if that is possible at all and how difficult it would be.

it seems not terribly safe, since you don't really have much control
over where the memory comes from w/ userptr.  I'm more in favor of
discouraging usage of userptr

BR,
-R