On 01/10/2017 03:41 PM, Laurent Pinchart wrote:
> On Tuesday 10 Jan 2017 08:55:16 Vincent ABRIOU wrote:
>> On 01/09/2017 05:59 PM, Laurent Pinchart wrote:
>>> On Monday 09 Jan 2017 15:49:00 Vincent ABRIOU wrote:
>>>> On 01/09/2017 04:37 PM, Laurent Pinchart wrote:
>>>>> Hi Vincent,
>>>>>
>>>>> Thank you for the patch.
>>>>>
>>>>> On Monday 03 Oct 2016 13:27:16 Vincent Abriou wrote:
>>>>>> Allow uvcvideo compatible devices to allocate their output buffers
>>>>>> using contiguous DMA buffers.
>>>>>
>>>>> Why do you need this ? If it's for buffer sharing with a device that
>>>>> requires dma-contig, can't you allocate the buffers on the other device
>>>>> and import them on the UVC side ?
>>>>
>>>> Hi Laurent,
>>>>
>>>> I need this using Gstreamer simple pipeline to connect an usb webcam
>>>> (v4l2src) with a display (waylandsink) activating the zero copy path.
>>>>
>>>> The waylandsink plugin does not have any contiguous memory pool to
>>>> allocate contiguous buffer. So it is up to the upstream element, here
>>>> v4l2src, to provide such contiguous buffers.
>>>
>>> Isn't that a gstreamer issue ?
>>
>> It is not a gstreamer issue. It is the way it has been decided to work.
>> Waylandsink accept DMABUF contiguous buffer but it does not have its own
>> buffer pool.
>
> But why do you put the blame on the kernel when you decide to take the wrong
> decision in userspace ? :-)
>

I don't blame the kernel... I improve it :)

>>>>>> Add the "allocators" module parameter option to let uvcvideo use the
>>>>>> dma-contig instead of vmalloc.
>>>>>>
>>>>>> Signed-off-by: Vincent Abriou <vincent.abr...@st.com>
>>>>>> ---
>>>>>>
>>>>>>  Documentation/media/v4l-drivers/uvcvideo.rst | 12 ++++++++++++
>>>>>>  drivers/media/usb/uvc/Kconfig                |  2 ++
>>>>>>  drivers/media/usb/uvc/uvc_driver.c           |  3 ++-
>>>>>>  drivers/media/usb/uvc/uvc_queue.c            | 23 ++++++++++++++++---
>>>>>>  drivers/media/usb/uvc/uvcvideo.h             |  4 ++--
>>>>>>  5 files changed, 38 insertions(+), 6 deletions(-)
>--
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