From: Gustavo Padovan <gustavo@padovan.org>
To: linux-media@vger.kernel.org
Cc: kernel@collabora.com, Hans Verkuil <hverkuil@xs4all.nl>,
Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
Shuah Khan <shuahkh@osg.samsung.com>,
Pawel Osciak <pawel@osciak.com>,
Alexandre Courbot <acourbot@chromium.org>,
Sakari Ailus <sakari.ailus@iki.fi>,
Brian Starkey <brian.starkey@arm.com>,
linux-kernel@vger.kernel.org,
Gustavo Padovan <gustavo.padovan@collabora.com>
Subject: [PATCH v8 08/13] [media] vb2: add explicit fence user API
Date: Fri, 9 Mar 2018 14:49:15 -0300 [thread overview]
Message-ID: <20180309174920.22373-9-gustavo@padovan.org> (raw)
In-Reply-To: <20180309174920.22373-1-gustavo@padovan.org>
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 or 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.
v6: - big improvement on doc (Hans Verkuil)
v5:
- keep using reserved2 field for cpia2
- set fence_fd to 0 for now, for compat with userspace(Mauro)
v4:
- make it a union with reserved2 and fence_fd (Hans Verkuil)
v3:
- make the out_fence refer to the current buffer (Hans Verkuil)
v2: add documentation
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
---
Documentation/media/uapi/v4l/buffer.rst | 45 +++++++++++++++++++++++--
drivers/media/common/videobuf2/videobuf2-v4l2.c | 2 +-
drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 4 +--
include/uapi/linux/videodev2.h | 7 +++-
4 files changed, 51 insertions(+), 7 deletions(-)
diff --git a/Documentation/media/uapi/v4l/buffer.rst b/Documentation/media/uapi/v4l/buffer.rst
index e2c85ddc990b..49273026740f 100644
--- a/Documentation/media/uapi/v4l/buffer.rst
+++ b/Documentation/media/uapi/v4l/buffer.rst
@@ -301,10 +301,22 @@ struct v4l2_buffer
elements in the ``planes`` array. The driver will fill in the
actual number of valid elements in that array.
* - __u32
- - ``reserved2``
+ - ``fence_fd``
-
- - A place holder for future extensions. Drivers and applications
- must set this to 0.
+ - Used to communicate fences file descriptors from userspace to kernel
+ and vice-versa. On :ref:`VIDIOC_QBUF <VIDIOC_QBUF>` when sending
+ an in-fence for V4L2 to wait on, the ``V4L2_BUF_FLAG_IN_FENCE`` flag must
+ be used and this field set to the fence file descriptor of the in-fence
+ If the in-fence is not valid ` VIDIOC_QBUF`` returns an error.
+
+ To get an out-fence back from V4L2 the ``V4L2_BUF_FLAG_OUT_FENCE``
+ must be set, the kernel will return the out-fence file descriptor on
+ this field. If it fails to create the out-fence ``VIDIOC_QBUF` returns
+ an error.
+
+ In all other ioctls V4L2 sets this field to -1 if
+ ``V4L2_BUF_FLAG_IN_FENCE`` and/or ``V4L2_BUF_FLAG_OUT_FENCE`` are set,
+ otherwise this field is set to 0 for backward compatibility.
* - __u32
- ``reserved``
-
@@ -648,6 +660,33 @@ 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 the fence passed in the ``fence_fd`` field. The
+ buffer won't be queued to the driver until the fence signals. The order
+ in which buffers are queued is guaranteed to be preserved, so any
+ buffers queued after this buffer will also be blocked until this fence
+ signals. This flag must be set before calling ``VIDIOC_QBUF``. For
+ other ioctls the driver just report the value of the flag.
+
+ If the fence signals the flag is cleared and not reported anymore.
+ If the fence is not valid ``VIDIOC_QBUF`` returns an error.
+
+
+ * .. _`V4L2-BUF-FLAG-OUT-FENCE`:
+
+ - ``V4L2_BUF_FLAG_OUT_FENCE``
+ - 0x00400000
+ - Request for a fence to be attached to the buffer. The driver will fill
+ in the out-fence fd in the ``fence_fd`` field when :ref:`VIDIOC_QBUF
+ <VIDIOC_QBUF>` returns. This flag must be set before calling
+ ``VIDIOC_QBUF``. For other ioctls the driver just report the value of
+ the flag.
+
+ If the creation of the out-fence fails ``VIDIOC_QBUF`` returns an
+ error.
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 68291ba8632d..ad1e032c3bf5 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/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 = 0;
b->reserved = 0;
if (q->is_multiplanar) {
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 5198c9eeb348..3de2252e3632 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -386,7 +386,7 @@ struct v4l2_buffer32 {
__s32 fd;
} m;
__u32 length;
- __u32 reserved2;
+ __s32 fence_fd;
__u32 reserved;
};
@@ -604,7 +604,7 @@ static int put_v4l2_buffer32(struct v4l2_buffer __user *kp,
assign_in_user(&up->timestamp.tv_usec, &kp->timestamp.tv_usec) ||
copy_in_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
assign_in_user(&up->sequence, &kp->sequence) ||
- assign_in_user(&up->reserved2, &kp->reserved2) ||
+ assign_in_user(&up->fence_fd, &kp->fence_fd) ||
assign_in_user(&up->reserved, &kp->reserved) ||
get_user(length, &kp->length) ||
put_user(length, &up->length))
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 58894cfe9479..2d424aebdd1e 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -933,7 +933,10 @@ struct v4l2_buffer {
__s32 fd;
} m;
__u32 length;
- __u32 reserved2;
+ union {
+ __s32 fence_fd;
+ __u32 reserved2;
+ };
__u32 reserved;
};
@@ -970,6 +973,8 @@ 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
--
2.14.3
next prev parent reply other threads:[~2018-03-09 17:50 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-09 17:49 [PATCH v8 00/13] V4L2 Explicit Synchronization Gustavo Padovan
2018-03-09 17:49 ` [PATCH v8 01/13] [media] xilinx: regroup caps on querycap Gustavo Padovan
2018-03-14 2:30 ` Hans Verkuil
2018-03-09 17:49 ` [PATCH v8 02/13] [media] hackrf: group device capabilities Gustavo Padovan
2018-03-09 17:49 ` [PATCH v8 03/13] [media] omap3isp: " Gustavo Padovan
2018-03-14 2:34 ` Hans Verkuil
2018-03-09 17:49 ` [PATCH v8 04/13] [media] vb2: add is_unordered callback for drivers Gustavo Padovan
2018-03-14 2:44 ` Hans Verkuil
2018-03-09 17:49 ` [PATCH v8 05/13] [media] v4l: add 'unordered' flag to format description ioctl Gustavo Padovan
2018-03-09 17:49 ` [PATCH v8 06/13] [media] cobalt: add .is_unordered() for cobalt Gustavo Padovan
2018-03-14 2:48 ` Hans Verkuil
2018-03-09 17:49 ` [PATCH v8 07/13] [media] vb2: mark codec drivers as unordered Gustavo Padovan
2018-03-09 18:51 ` Nicolas Dufresne
2018-03-14 2:57 ` Hans Verkuil
2018-03-09 17:49 ` Gustavo Padovan [this message]
2018-03-14 3:06 ` [PATCH v8 08/13] [media] vb2: add explicit fence user API Hans Verkuil
2018-03-09 17:49 ` [PATCH v8 09/13] [media] vb2: add in-fence support to QBUF Gustavo Padovan
2018-03-14 15:55 ` Hans Verkuil
2018-04-25 20:11 ` Ezequiel Garcia
2018-04-26 6:27 ` Hans Verkuil
2018-03-09 17:49 ` [PATCH v8 10/13] [media] vb2: add out-fence " Gustavo Padovan
2018-03-14 16:25 ` Hans Verkuil
2018-04-30 15:27 ` Ezequiel Garcia
2018-03-09 17:49 ` [PATCH v8 11/13] [media] v4l: introduce the fences capability Gustavo Padovan
2018-03-14 3:12 ` Hans Verkuil
2018-03-09 17:49 ` [PATCH v8 12/13] [media] v4l: Add V4L2_CAP_FENCES to drivers Gustavo Padovan
2018-03-14 16:07 ` Hans Verkuil
2018-03-09 17:49 ` [PATCH v8 13/13] [media] v4l: Document explicit synchronization behavior Gustavo Padovan
2018-03-13 9:26 ` jacopo mondi
2018-03-14 3:33 ` Hans Verkuil
2018-03-14 16:01 ` Hans Verkuil
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