* [PATCH 1/1] v4l: uAPI doc: Changing frame interval won't change format
@ 2018-11-21 17:33 Sakari Ailus
2018-11-22 9:08 ` Hans Verkuil
0 siblings, 1 reply; 2+ messages in thread
From: Sakari Ailus @ 2018-11-21 17:33 UTC (permalink / raw)
To: linux-media; +Cc: hverkuil
Document that changing the frame interval has no effect on frame size.
While this was the assumption in the API, it was not documented as such.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
Documentation/media/uapi/v4l/vidioc-g-parm.rst | 3 +++
Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst | 3 +++
2 files changed, 6 insertions(+)
diff --git a/Documentation/media/uapi/v4l/vidioc-g-parm.rst b/Documentation/media/uapi/v4l/vidioc-g-parm.rst
index e831fa5512f0..c31585a7701b 100644
--- a/Documentation/media/uapi/v4l/vidioc-g-parm.rst
+++ b/Documentation/media/uapi/v4l/vidioc-g-parm.rst
@@ -42,6 +42,9 @@ side. This is especially useful when using the :ref:`read() <func-read>` or
:ref:`write() <func-write>`, which are not augmented by timestamps or sequence
counters, and to avoid unnecessary data copying.
+Changing the frame interval shall never change the format. Changing the
+format, on the other hand, may change the frame interval.
+
Further these ioctls can be used to determine the number of buffers used
internally by a driver in read/write mode. For implications see the
section discussing the :ref:`read() <func-read>` function.
diff --git a/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst b/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst
index 5af0a7179941..f889c20f231c 100644
--- a/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst
+++ b/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst
@@ -63,6 +63,9 @@ doesn't match the device capabilities. They must instead modify the
interval to match what the hardware can provide. The modified interval
should be as close as possible to the original request.
+Changing the frame interval shall never change the format. Changing the
+format, on the other hand, may change the frame interval.
+
Sub-devices that support the frame interval ioctls should implement them
on a single pad only. Their behaviour when supported on multiple pads of
the same sub-device is not defined.
--
2.11.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH 1/1] v4l: uAPI doc: Changing frame interval won't change format
2018-11-21 17:33 [PATCH 1/1] v4l: uAPI doc: Changing frame interval won't change format Sakari Ailus
@ 2018-11-22 9:08 ` Hans Verkuil
0 siblings, 0 replies; 2+ messages in thread
From: Hans Verkuil @ 2018-11-22 9:08 UTC (permalink / raw)
To: Sakari Ailus, linux-media
On 11/21/2018 06:33 PM, Sakari Ailus wrote:
> Document that changing the frame interval has no effect on frame size.
> While this was the assumption in the API, it was not documented as such.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Thanks!
Hans
> ---
> Documentation/media/uapi/v4l/vidioc-g-parm.rst | 3 +++
> Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst | 3 +++
> 2 files changed, 6 insertions(+)
>
> diff --git a/Documentation/media/uapi/v4l/vidioc-g-parm.rst b/Documentation/media/uapi/v4l/vidioc-g-parm.rst
> index e831fa5512f0..c31585a7701b 100644
> --- a/Documentation/media/uapi/v4l/vidioc-g-parm.rst
> +++ b/Documentation/media/uapi/v4l/vidioc-g-parm.rst
> @@ -42,6 +42,9 @@ side. This is especially useful when using the :ref:`read() <func-read>` or
> :ref:`write() <func-write>`, which are not augmented by timestamps or sequence
> counters, and to avoid unnecessary data copying.
>
> +Changing the frame interval shall never change the format. Changing the
> +format, on the other hand, may change the frame interval.
> +
> Further these ioctls can be used to determine the number of buffers used
> internally by a driver in read/write mode. For implications see the
> section discussing the :ref:`read() <func-read>` function.
> diff --git a/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst b/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst
> index 5af0a7179941..f889c20f231c 100644
> --- a/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst
> +++ b/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst
> @@ -63,6 +63,9 @@ doesn't match the device capabilities. They must instead modify the
> interval to match what the hardware can provide. The modified interval
> should be as close as possible to the original request.
>
> +Changing the frame interval shall never change the format. Changing the
> +format, on the other hand, may change the frame interval.
> +
> Sub-devices that support the frame interval ioctls should implement them
> on a single pad only. Their behaviour when supported on multiple pads of
> the same sub-device is not defined.
>
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