lkml.org 
[lkml]   [2017]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v3 02/15] [media] vb2: add explicit fence user API
Date
From: Gustavo Padovan <gustavo.padovan@collabora.com>

Turn the reserved2 field into fence_fd that we will use to send
an in-fence to the kernel and return an out-fence from the kernel to
userspace.

Two new flags were added, V4L2_BUF_FLAG_IN_FENCE, that should be used
when sending a fence to the kernel to be waited on, and
V4L2_BUF_FLAG_OUT_FENCE, to ask the kernel to give back an out-fence.

v2: add documentation

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
---
Documentation/media/uapi/v4l/buffer.rst | 19 +++++++++++++++++++
drivers/media/usb/cpia2/cpia2_v4l.c | 2 +-
drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 4 ++--
drivers/media/v4l2-core/videobuf2-v4l2.c | 2 +-
include/uapi/linux/videodev2.h | 4 +++-
5 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/Documentation/media/uapi/v4l/buffer.rst b/Documentation/media/uapi/v4l/buffer.rst
index ae6ee73f151c..664507ad06c6 100644
--- a/Documentation/media/uapi/v4l/buffer.rst
+++ b/Documentation/media/uapi/v4l/buffer.rst
@@ -648,6 +648,25 @@ Buffer Flags
- Start Of Exposure. The buffer timestamp has been taken when the
exposure of the frame has begun. This is only valid for the
``V4L2_BUF_TYPE_VIDEO_CAPTURE`` buffer type.
+ * .. _`V4L2-BUF-FLAG-IN-FENCE`:
+
+ - ``V4L2_BUF_FLAG_IN_FENCE``
+ - 0x00200000
+ - Ask V4L2 to wait on fence passed in ``fence_fd`` field. The buffer
+ won't be queued to the driver until the fence signals.
+
+ * .. _`V4L2-BUF-FLAG-OUT-FENCE`:
+
+ - ``V4L2_BUF_FLAG_OUT_FENCE``
+ - 0x00400000
+ - Request a fence for the next buffer to be queued to V4L2 driver.
+ The fence received back through the ``fence_fd`` field doesn't
+ necessarily relate to the current buffer in the
+ :ref:`VIDIOC_QBUF <VIDIOC_QBUF>` ioctl. Although, most of the time
+ the fence will relate to the current buffer it can't be guaranteed.
+ So to tell userspace which buffer is associated to the out_fence,
+ one should listen for the ``V4L2_EVENT_BUF_QUEUED`` event that
+ provide the id of the buffer when it is queued to the V4L2 driver.



diff --git a/drivers/media/usb/cpia2/cpia2_v4l.c b/drivers/media/usb/cpia2/cpia2_v4l.c
index 3dedd83f0b19..6cde686bf44c 100644
--- a/drivers/media/usb/cpia2/cpia2_v4l.c
+++ b/drivers/media/usb/cpia2/cpia2_v4l.c
@@ -948,7 +948,7 @@ static int cpia2_dqbuf(struct file *file, void *fh, struct v4l2_buffer *buf)
buf->sequence = cam->buffers[buf->index].seq;
buf->m.offset = cam->buffers[buf->index].data - cam->frame_buffer;
buf->length = cam->frame_size;
- buf->reserved2 = 0;
+ buf->fence_fd = -1;
buf->reserved = 0;
memset(&buf->timecode, 0, sizeof(buf->timecode));

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 821f2aa299ae..d624fb5df130 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -370,7 +370,7 @@ struct v4l2_buffer32 {
__s32 fd;
} m;
__u32 length;
- __u32 reserved2;
+ __s32 fence_fd;
__u32 reserved;
};

@@ -533,8 +533,8 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
put_user(kp->timestamp.tv_usec, &up->timestamp.tv_usec) ||
copy_to_user(&up->timecode, &kp->timecode, sizeof(struct v4l2_timecode)) ||
put_user(kp->sequence, &up->sequence) ||
- put_user(kp->reserved2, &up->reserved2) ||
put_user(kp->reserved, &up->reserved) ||
+ put_user(kp->fence_fd, &up->fence_fd) ||
put_user(kp->length, &up->length))
return -EFAULT;

diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c
index 0c0669976bdc..110fb45fef6f 100644
--- a/drivers/media/v4l2-core/videobuf2-v4l2.c
+++ b/drivers/media/v4l2-core/videobuf2-v4l2.c
@@ -203,7 +203,7 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, void *pb)
b->timestamp = ns_to_timeval(vb->timestamp);
b->timecode = vbuf->timecode;
b->sequence = vbuf->sequence;
- b->reserved2 = 0;
+ b->fence_fd = -1;
b->reserved = 0;

if (q->is_multiplanar) {
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 185d6a0acc06..e5abab9a908c 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -924,7 +924,7 @@ struct v4l2_buffer {
__s32 fd;
} m;
__u32 length;
- __u32 reserved2;
+ __s32 fence_fd;
__u32 reserved;
};

@@ -961,6 +961,8 @@ struct v4l2_buffer {
#define V4L2_BUF_FLAG_TSTAMP_SRC_SOE 0x00010000
/* mem2mem encoder/decoder */
#define V4L2_BUF_FLAG_LAST 0x00100000
+#define V4L2_BUF_FLAG_IN_FENCE 0x00200000
+#define V4L2_BUF_FLAG_OUT_FENCE 0x00400000

/**
* struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor
--
2.13.5
\
 
 \ /
  Last update: 2017-09-07 20:48    [W:0.197 / U:26.664 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site