Re: [PATCHv2] videodev2.h: add V4L2_BUF_CAP_SUPPORTS_PREPARE_BUF/CREATE_BUFS
On 11/29/2018 10:30 AM, Hans Verkuil wrote:
> Add new buffer capability flags to indicate if the VIDIOC_PREPARE_BUF or
> VIDIOC_CREATE_BUFS ioctls are supported.
>
> The reason for this is that there is currently no way for an application
> to detect if VIDIOC_PREPARE_BUF is implemented other than trying it, but
> then the buffer is already prepared. You would like to know this before
> taking an irreversible action.
>
> Since we need V4L2_BUF_CAP_SUPPORTS_PREPARE_BUF it makes sense to add
> V4L2_BUF_CAP_SUPPORTS_CREATE_BUFS as well because not all drivers support
> this ioctl.
>
> Signed-off-by: Hans Verkuil
> Acked-by: Sakari Ailus
> ---
> Changes since v1:
>
> - rebased
> - improved commit msg
> - added missing include for media/v4l2-ioctl.h
> ---
> Documentation/media/uapi/v4l/vidioc-reqbufs.rst | 8
> drivers/media/common/videobuf2/videobuf2-v4l2.c | 15 +--
> include/uapi/linux/videodev2.h | 12 +++-
> 3 files changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> index e62a15782790..092d6373380a 100644
> --- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> +++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> @@ -118,6 +118,8 @@ aborting or finishing any DMA in progress, an implicit
> .. _V4L2-BUF-CAP-SUPPORTS-DMABUF:
> .. _V4L2-BUF-CAP-SUPPORTS-REQUESTS:
> .. _V4L2-BUF-CAP-SUPPORTS-ORPHANED-BUFS:
> +.. _V4L2-BUF-CAP-SUPPORTS-PREPARE-BUF:
> +.. _V4L2-BUF-CAP-SUPPORTS-CREATE-BUFS:
>
> .. cssclass:: longtable
>
> @@ -143,6 +145,12 @@ aborting or finishing any DMA in progress, an implicit
>- The kernel allows calling :ref:`VIDIOC_REQBUFS` while buffers are
> still
> mapped or exported via DMABUF. These orphaned buffers will be freed
> when they are unmapped or when the exported DMABUF fds are closed.
> +* - ``V4L2_BUF_CAP_SUPPORTS_PREPARE_BUF``
> + - 0x0020
> + - This buffer type supports :ref:`VIDIOC_PREPARE_BUF`.
> +* - ``V4L2_BUF_CAP_SUPPORTS_CREATE_BUFS``
> + - 0x0040
> + - This buffer type supports :ref:`VIDIOC_CREATE_BUFS`.
>
> Return Value
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index 1244c246d0c4..5273f574fb7a 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -28,6 +28,7 @@
> #include
> #include
> #include
> +#include
> #include
>
> #include
> @@ -870,6 +871,16 @@ static inline bool vb2_queue_is_busy(struct video_device
> *vdev, struct file *fil
> return vdev->queue->owner && vdev->queue->owner != file->private_data;
> }
>
> +static void fill_buf_caps_vdev(struct video_device *vdev, u32 *caps)
> +{
> + *caps = 0;
> + fill_buf_caps(vdev->queue, caps);
> + if (vdev->ioctl_ops->vidioc_prepare_buf)
> + *caps |= V4L2_BUF_CAP_SUPPORTS_PREPARE_BUF;
> + if (vdev->ioctl_ops->vidioc_create_bufs)
> + *caps |= V4L2_BUF_CAP_SUPPORTS_CREATE_BUFS;
> +}
> +
> /* vb2 ioctl helpers */
>
> int vb2_ioctl_reqbufs(struct file *file, void *priv,
> @@ -878,7 +889,7 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
> struct video_device *vdev = video_devdata(file);
> int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
>
> - fill_buf_caps(vdev->queue, >capabilities);
> + fill_buf_caps_vdev(vdev, >capabilities);
> if (res)
> return res;
> if (vb2_queue_is_busy(vdev, file))
> @@ -900,7 +911,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
> p->format.type);
>
> p->index = vdev->queue->num_buffers;
> - fill_buf_caps(vdev->queue, >capabilities);
> + fill_buf_caps_vdev(vdev, >capabilities);
> /*
>* If count == 0, then just check if memory and type are valid.
>* Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 2a223835214c..8ebc66e311e0 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -875,11 +875,13 @@ struct v4l2_requestbuffers {
> };
>
> /* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */
> -#define V4L2_BUF_CAP_SUPPORTS_MMAP (1 << 0)
> -#define V4L2_BUF_CAP_SUPPORTS_USERPTR(1 << 1)
> -#define V4L2_BUF_CAP_SUPPORTS_DMABUF (1 << 2)
> -#define V4L2_BUF_CAP_SUPPORTS_REQUESTS (1 << 3)
> -#define V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS (1 << 4)
> +#define V4L2_BUF_CAP_SUPPORTS_MMAP (1 << 0)
> +#define V4L2_BUF_CAP_SUPPORTS_USERPTR(1 << 1)
> +#define V4L2_BUF_CAP_SUPPORTS_DMABUF (1 << 2)
> +#define V4L2_BUF_CAP_SUPPORTS_REQUESTS (1 << 3)
> +#define V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS (1 << 4)
> +#define
[PATCHv2] videodev2.h: add V4L2_BUF_CAP_SUPPORTS_PREPARE_BUF/CREATE_BUFS
Add new buffer capability flags to indicate if the VIDIOC_PREPARE_BUF or
VIDIOC_CREATE_BUFS ioctls are supported.
The reason for this is that there is currently no way for an application
to detect if VIDIOC_PREPARE_BUF is implemented other than trying it, but
then the buffer is already prepared. You would like to know this before
taking an irreversible action.
Since we need V4L2_BUF_CAP_SUPPORTS_PREPARE_BUF it makes sense to add
V4L2_BUF_CAP_SUPPORTS_CREATE_BUFS as well because not all drivers support
this ioctl.
Signed-off-by: Hans Verkuil
Acked-by: Sakari Ailus
---
Changes since v1:
- rebased
- improved commit msg
- added missing include for media/v4l2-ioctl.h
---
Documentation/media/uapi/v4l/vidioc-reqbufs.rst | 8
drivers/media/common/videobuf2/videobuf2-v4l2.c | 15 +--
include/uapi/linux/videodev2.h | 12 +++-
3 files changed, 28 insertions(+), 7 deletions(-)
diff --git a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
index e62a15782790..092d6373380a 100644
--- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
+++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
@@ -118,6 +118,8 @@ aborting or finishing any DMA in progress, an implicit
.. _V4L2-BUF-CAP-SUPPORTS-DMABUF:
.. _V4L2-BUF-CAP-SUPPORTS-REQUESTS:
.. _V4L2-BUF-CAP-SUPPORTS-ORPHANED-BUFS:
+.. _V4L2-BUF-CAP-SUPPORTS-PREPARE-BUF:
+.. _V4L2-BUF-CAP-SUPPORTS-CREATE-BUFS:
.. cssclass:: longtable
@@ -143,6 +145,12 @@ aborting or finishing any DMA in progress, an implicit
- The kernel allows calling :ref:`VIDIOC_REQBUFS` while buffers are still
mapped or exported via DMABUF. These orphaned buffers will be freed
when they are unmapped or when the exported DMABUF fds are closed.
+* - ``V4L2_BUF_CAP_SUPPORTS_PREPARE_BUF``
+ - 0x0020
+ - This buffer type supports :ref:`VIDIOC_PREPARE_BUF`.
+* - ``V4L2_BUF_CAP_SUPPORTS_CREATE_BUFS``
+ - 0x0040
+ - This buffer type supports :ref:`VIDIOC_CREATE_BUFS`.
Return Value
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c
b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 1244c246d0c4..5273f574fb7a 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -28,6 +28,7 @@
#include
#include
#include
+#include
#include
#include
@@ -870,6 +871,16 @@ static inline bool vb2_queue_is_busy(struct video_device
*vdev, struct file *fil
return vdev->queue->owner && vdev->queue->owner != file->private_data;
}
+static void fill_buf_caps_vdev(struct video_device *vdev, u32 *caps)
+{
+ *caps = 0;
+ fill_buf_caps(vdev->queue, caps);
+ if (vdev->ioctl_ops->vidioc_prepare_buf)
+ *caps |= V4L2_BUF_CAP_SUPPORTS_PREPARE_BUF;
+ if (vdev->ioctl_ops->vidioc_create_bufs)
+ *caps |= V4L2_BUF_CAP_SUPPORTS_CREATE_BUFS;
+}
+
/* vb2 ioctl helpers */
int vb2_ioctl_reqbufs(struct file *file, void *priv,
@@ -878,7 +889,7 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
struct video_device *vdev = video_devdata(file);
int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
- fill_buf_caps(vdev->queue, >capabilities);
+ fill_buf_caps_vdev(vdev, >capabilities);
if (res)
return res;
if (vb2_queue_is_busy(vdev, file))
@@ -900,7 +911,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
p->format.type);
p->index = vdev->queue->num_buffers;
- fill_buf_caps(vdev->queue, >capabilities);
+ fill_buf_caps_vdev(vdev, >capabilities);
/*
* If count == 0, then just check if memory and type are valid.
* Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 2a223835214c..8ebc66e311e0 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -875,11 +875,13 @@ struct v4l2_requestbuffers {
};
/* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */
-#define V4L2_BUF_CAP_SUPPORTS_MMAP (1 << 0)
-#define V4L2_BUF_CAP_SUPPORTS_USERPTR (1 << 1)
-#define V4L2_BUF_CAP_SUPPORTS_DMABUF (1 << 2)
-#define V4L2_BUF_CAP_SUPPORTS_REQUESTS (1 << 3)
-#define V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS (1 << 4)
+#define V4L2_BUF_CAP_SUPPORTS_MMAP (1 << 0)
+#define V4L2_BUF_CAP_SUPPORTS_USERPTR (1 << 1)
+#define V4L2_BUF_CAP_SUPPORTS_DMABUF (1 << 2)
+#define V4L2_BUF_CAP_SUPPORTS_REQUESTS (1 << 3)
+#define V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS(1 << 4)
+#define V4L2_BUF_CAP_SUPPORTS_PREPARE_BUF (1 << 5)
+#define V4L2_BUF_CAP_SUPPORTS_CREATE_BUFS (1 << 6)
/**
* struct v4l2_plane - plane info for multi-planar buffers
--
2.19.1
