[libcamera-devel] [PATCH v2] v4l2: V4L2CameraProxy: Add support for DMABUF buffer I/O in REQBUF ioctl

[Vedant Paranjape]

Hi Laurent,
I wanted to send this as an RFC, my bad.

On Tue, Nov 30, 2021 at 2:55 PM Laurent Pinchart
<laurent.pinchart at ideasonboard.com> wrote:
>
> Hi Vedant,
>
> On Tue, Nov 30, 2021 at 02:28:30PM +0530, Vedant Paranjape wrote:
> > To support importing DMABUF, we need to reqbufs with DMABUF mode.
> >
> > This patch enables using V4L2_MEMORY_DMABUF as one of the memory types
> > in vidioc_reqbuf to initialise DMA Buffer I/O
>
> Have you tested that this patch enables DMABUF support ?
>
> > Bug: https://bugs.libcamera.org/show_bug.cgi?id=89
> >
> > Signed-off-by: Vedant Paranjape <vedantparanjape160201 at gmail.com>
> > ---
> >  src/v4l2/v4l2_camera_proxy.cpp | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
> > index f194e06345b7..49db766d9f9d 100644
> > --- a/src/v4l2/v4l2_camera_proxy.cpp
> > +++ b/src/v4l2/v4l2_camera_proxy.cpp
> > @@ -160,7 +160,8 @@ bool V4L2CameraProxy::validateBufferType(uint32_t type)
> >
> >  bool V4L2CameraProxy::validateMemoryType(uint32_t memory)
> >  {
> > -     return memory == V4L2_MEMORY_MMAP;
> > +     return (memory == V4L2_MEMORY_MMAP) ||
> > +            (memory == V4L2_MEMORY_DMABUF);
>
> No need for parentheses.
>
> As pointed by Paul, this introduces an issue in the EXPBUF
> implementation.
>
> Please stop ignoring review comments when sending new versions, or I'll
> have to ignore your patches.

I'm extremely sorry, didn't mean to ignore. I had a chat with Paul
regarding solving this, I wanted to send this as an RFC instead.

>
> >  }
> >
> >  void V4L2CameraProxy::setFmtFromConfig(const StreamConfiguration &streamConfig)
> > @@ -468,7 +469,8 @@ int V4L2CameraProxy::vidioc_reqbufs(V4L2CameraFile *file, struct v4l2_requestbuf
> >       if (!hasOwnership(file) && owner_)
> >               return -EBUSY;
> >
> > -     arg->capabilities = V4L2_BUF_CAP_SUPPORTS_MMAP;
> > +     arg->capabilities = V4L2_BUF_CAP_SUPPORTS_MMAP |
> > +                         V4L2_BUF_CAP_SUPPORTS_DMABUF;
> >       memset(arg->reserved, 0, sizeof(arg->reserved));
> >
> >       if (arg->count == 0) {
> > @@ -511,7 +513,7 @@ int V4L2CameraProxy::vidioc_reqbufs(V4L2CameraFile *file, struct v4l2_requestbuf
> >               struct v4l2_buffer buf = {};
> >               buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> >               buf.length = v4l2PixFormat_.sizeimage;
> > -             buf.memory = V4L2_MEMORY_MMAP;
> > +             buf.memory = arg->memory;
> >               buf.m.offset = i * v4l2PixFormat_.sizeimage;
> >               buf.index = i;
> >               buf.flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
>
> --
> Regards,
>
> Laurent Pinchart

Regards,
Vedant Paranjape