Make it clear in the documentation that V4L2_CTRL_FLAG_READ_ONLY doesn't
conflict with V4L2_CTRL_FLAG_WRITE_ONLY. Also make it clear that
if both are combined then the control has read and write permissions.
Signed-off-by: Helen Koike <[email protected]>
---
Hi,
v4l2-compliance expects both flags for read and write permissions, so I
would like to make it clear in the docs.
Please let me know if this is not the case.
Thanks
Helen
---
Documentation/media/uapi/v4l/vidioc-queryctrl.rst | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
index a3d56ffbf4cc..1d3aecdf679f 100644
--- a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
+++ b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
@@ -500,6 +500,11 @@ See also the examples in :ref:`control`.
- 0x0004
- This control is permanently readable only. Any attempt to change
the control will result in an ``EINVAL`` error code.
+
+ .. note::
+
+ If combined with ``V4L2_CTRL_FLAG_WRITE_ONLY``, then both, read
+ and write are allowed.
* - ``V4L2_CTRL_FLAG_UPDATE``
- 0x0008
- A hint that changing this control may affect the value of other
@@ -523,6 +528,11 @@ See also the examples in :ref:`control`.
where writing a value will cause the device to carry out a given
action (e. g. motor control) but no meaningful value can be
returned.
+
+ .. note::
+
+ If combined with ``V4L2_CTRL_FLAG_READ_ONLY``, then both, read
+ and write are allowed.
* - ``V4L2_CTRL_FLAG_VOLATILE``
- 0x0080
- This control is volatile, which means that the value of the
--
2.22.0
On 9/25/19 5:09 PM, Helen Koike wrote:
> Make it clear in the documentation that V4L2_CTRL_FLAG_READ_ONLY doesn't
> conflict with V4L2_CTRL_FLAG_WRITE_ONLY. Also make it clear that
> if both are combined then the control has read and write permissions.
That doesn't look right.
This is the test in v4l2-compliance:
__u32 rw_mask = V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY;
if ((fl & rw_mask) == rw_mask)
return fail("can't read nor write this control\n");
If both flags are set, then a fail is reported.
Did you mis-read?
Setting both flags makes no sense.
Regards,
Hans
>
> Signed-off-by: Helen Koike <[email protected]>
>
> ---
> Hi,
>
> v4l2-compliance expects both flags for read and write permissions, so I
> would like to make it clear in the docs.
> Please let me know if this is not the case.
>
> Thanks
> Helen
> ---
> Documentation/media/uapi/v4l/vidioc-queryctrl.rst | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
> index a3d56ffbf4cc..1d3aecdf679f 100644
> --- a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
> +++ b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
> @@ -500,6 +500,11 @@ See also the examples in :ref:`control`.
> - 0x0004
> - This control is permanently readable only. Any attempt to change
> the control will result in an ``EINVAL`` error code.
> +
> + .. note::
> +
> + If combined with ``V4L2_CTRL_FLAG_WRITE_ONLY``, then both, read
> + and write are allowed.
> * - ``V4L2_CTRL_FLAG_UPDATE``
> - 0x0008
> - A hint that changing this control may affect the value of other
> @@ -523,6 +528,11 @@ See also the examples in :ref:`control`.
> where writing a value will cause the device to carry out a given
> action (e. g. motor control) but no meaningful value can be
> returned.
> +
> + .. note::
> +
> + If combined with ``V4L2_CTRL_FLAG_READ_ONLY``, then both, read
> + and write are allowed.
> * - ``V4L2_CTRL_FLAG_VOLATILE``
> - 0x0080
> - This control is volatile, which means that the value of the
>
Hi Hans
On 9/25/19 12:17 PM, Hans Verkuil wrote:
> On 9/25/19 5:09 PM, Helen Koike wrote:
>> Make it clear in the documentation that V4L2_CTRL_FLAG_READ_ONLY doesn't
>> conflict with V4L2_CTRL_FLAG_WRITE_ONLY. Also make it clear that
>> if both are combined then the control has read and write permissions.
>
> That doesn't look right.
>
> This is the test in v4l2-compliance:
>
> __u32 rw_mask = V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY;
>
> if ((fl & rw_mask) == rw_mask)
> return fail("can't read nor write this control\n");
>
> If both flags are set, then a fail is reported.
>
> Did you mis-read?
>
> Setting both flags makes no sense.
Maybe I misunderstood the V4L2_CTRL_TYPE_CTRL_CLASS, from v4l2-compliance:
case V4L2_CTRL_TYPE_CTRL_CLASS:
if (fl != (V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY))
return fail("invalid flags for control class\n");
I was confused why vivid was using both flags in vivid_ctrl_class (and also the debayer patch that was following this model).
Why both flags are expected when this type is used?
Thanks,
Helen
>
> Regards,
>
> Hans
>
>>
>> Signed-off-by: Helen Koike <[email protected]>
>>
>> ---
>> Hi,
>>
>> v4l2-compliance expects both flags for read and write permissions, so I
>> would like to make it clear in the docs.
>> Please let me know if this is not the case.
>>
>> Thanks
>> Helen
>> ---
>> Documentation/media/uapi/v4l/vidioc-queryctrl.rst | 10 ++++++++++
>> 1 file changed, 10 insertions(+)
>>
>> diff --git a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
>> index a3d56ffbf4cc..1d3aecdf679f 100644
>> --- a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
>> +++ b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
>> @@ -500,6 +500,11 @@ See also the examples in :ref:`control`.
>> - 0x0004
>> - This control is permanently readable only. Any attempt to change
>> the control will result in an ``EINVAL`` error code.
>> +
>> + .. note::
>> +
>> + If combined with ``V4L2_CTRL_FLAG_WRITE_ONLY``, then both, read
>> + and write are allowed.
>> * - ``V4L2_CTRL_FLAG_UPDATE``
>> - 0x0008
>> - A hint that changing this control may affect the value of other
>> @@ -523,6 +528,11 @@ See also the examples in :ref:`control`.
>> where writing a value will cause the device to carry out a given
>> action (e. g. motor control) but no meaningful value can be
>> returned.
>> +
>> + .. note::
>> +
>> + If combined with ``V4L2_CTRL_FLAG_READ_ONLY``, then both, read
>> + and write are allowed.
>> * - ``V4L2_CTRL_FLAG_VOLATILE``
>> - 0x0080
>> - This control is volatile, which means that the value of the
>>
>
On 9/25/19 6:29 PM, Helen Koike wrote:
> Hi Hans
>
> On 9/25/19 12:17 PM, Hans Verkuil wrote:
>> On 9/25/19 5:09 PM, Helen Koike wrote:
>>> Make it clear in the documentation that V4L2_CTRL_FLAG_READ_ONLY doesn't
>>> conflict with V4L2_CTRL_FLAG_WRITE_ONLY. Also make it clear that
>>> if both are combined then the control has read and write permissions.
>>
>> That doesn't look right.
>>
>> This is the test in v4l2-compliance:
>>
>> __u32 rw_mask = V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY;
>>
>> if ((fl & rw_mask) == rw_mask)
>> return fail("can't read nor write this control\n");
>>
>> If both flags are set, then a fail is reported.
>>
>> Did you mis-read?
>>
>> Setting both flags makes no sense.
>
> Maybe I misunderstood the V4L2_CTRL_TYPE_CTRL_CLASS, from v4l2-compliance:
>
> case V4L2_CTRL_TYPE_CTRL_CLASS:
> if (fl != (V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY))
> return fail("invalid flags for control class\n");
>
> I was confused why vivid was using both flags in vivid_ctrl_class (and also the debayer patch that was following this model).
>
> Why both flags are expected when this type is used?
Ah, now I understand. This is specific to control classes: such controls cannot
be read nor written. They just provide a name for the control class, but both
G_CTRL and S_CTRL should fail.
So this specific combination of flags is specific to control classes only.
This works because a 'get' will fail if WRITE_ONLY is set, and a 'set' will fail
if READ_ONLY is set. Setting both flags will cause both 'get' and 'set' to fail.
It is admittedly a bit confusing.
Regards,
Hans
>
> Thanks,
> Helen
>
>>
>> Regards,
>>
>> Hans
>>
>>>
>>> Signed-off-by: Helen Koike <[email protected]>
>>>
>>> ---
>>> Hi,
>>>
>>> v4l2-compliance expects both flags for read and write permissions, so I
>>> would like to make it clear in the docs.
>>> Please let me know if this is not the case.
>>>
>>> Thanks
>>> Helen
>>> ---
>>> Documentation/media/uapi/v4l/vidioc-queryctrl.rst | 10 ++++++++++
>>> 1 file changed, 10 insertions(+)
>>>
>>> diff --git a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
>>> index a3d56ffbf4cc..1d3aecdf679f 100644
>>> --- a/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
>>> +++ b/Documentation/media/uapi/v4l/vidioc-queryctrl.rst
>>> @@ -500,6 +500,11 @@ See also the examples in :ref:`control`.
>>> - 0x0004
>>> - This control is permanently readable only. Any attempt to change
>>> the control will result in an ``EINVAL`` error code.
>>> +
>>> + .. note::
>>> +
>>> + If combined with ``V4L2_CTRL_FLAG_WRITE_ONLY``, then both, read
>>> + and write are allowed.
>>> * - ``V4L2_CTRL_FLAG_UPDATE``
>>> - 0x0008
>>> - A hint that changing this control may affect the value of other
>>> @@ -523,6 +528,11 @@ See also the examples in :ref:`control`.
>>> where writing a value will cause the device to carry out a given
>>> action (e. g. motor control) but no meaningful value can be
>>> returned.
>>> +
>>> + .. note::
>>> +
>>> + If combined with ``V4L2_CTRL_FLAG_READ_ONLY``, then both, read
>>> + and write are allowed.
>>> * - ``V4L2_CTRL_FLAG_VOLATILE``
>>> - 0x0080
>>> - This control is volatile, which means that the value of the
>>>
>>