Integer controls provide a way to get their default/initial value, but
any other control (p_u32, p_u8.....) provide no other way to get the
initial value than unloading the module and loading it back.
*What is the actual problem?
I have a custom control with WIDTH integer values. Every value
represents the calibrated FPN (fixed pattern noise) correction value for that
column
-Application A changes the FPN correction value
-Application B wants to restore the calibrated value but it cant :(
*What is the proposed solution?
(Kudos to Hans Verkuil!!!)
The key change is in struct v4l2_ext_controls where the __u32 ctrl_class field
is changed to:
union {
__u32 ctrl_class;
__u32 which;
};
And two new defines are added:
#define V4L2_CTRL_WHICH_CUR_VAL 0
#define V4L2_CTRL_WHICH_DEF_VAL 0x0f000000
The 'which' field tells you which controls are get/set/tried.
V4L2_CTRL_WHICH_CUR_VAL: the current value of the controls
V4L2_CTRL_WHICH_DEF_VAL: the default value of the controls
V4L2_CTRL_CLASS_*: the current value of the controls belonging to the specified class.
Note: this is deprecated usage and is only there for backwards compatibility.
Which is also why I don't think there is a need to add V4L2_CTRL_WHICH_
aliases for these defines.
I have posted a copy of my working tree to
https://github.com/ribalda/linux/tree/which_def
Changelog v1 (compared to v5 of New ioct VIDIOC_G_DEF_EXT_CTRLS):
Suggested by Hans Verkuil <hverkuil@xxxxxxxxx>
Replace ioctl implementation with a new union on the struct v4l2_ext_controls
THANKS!
Ricardo Ribalda Delgado (8):
videodev2.h: Fix typo in comment
videodev2.h: Extend struct v4l2_ext_controls
media/v4l2-core: struct struct v4l2_ext_controls param which
usb/uvc: Support for V4L2_CTRL_WHICH_DEF_VAL
media/usb/pvrusb2: Support for V4L2_CTRL_WHICH_DEF_VAL
media/pci/saa7164-encoder Support for V4L2_CTRL_WHICH_DEF_VAL
media/pci/saa7164-vbi Support for V4L2_CTRL_WHICH_DEF_VAL
Docbook: media: Document changes on struct v4l2_ext_controls
Documentation/DocBook/media/v4l/v4l2.xml | 9 ++++
.../DocBook/media/v4l/vidioc-g-ext-ctrls.xml | 14 ++++++
drivers/media/pci/saa7164/saa7164-encoder.c | 55 ++++++++++++---------
drivers/media/pci/saa7164/saa7164-vbi.c | 57 +++++++++++++---------
drivers/media/usb/pvrusb2/pvrusb2-v4l2.c | 17 ++++++-
drivers/media/usb/uvc/uvc_v4l2.c | 14 +++++-
drivers/media/v4l2-core/v4l2-ctrls.c | 35 +++++++++++--
include/uapi/linux/videodev2.h | 9 +++-
8 files changed, 153 insertions(+), 57 deletions(-)
--
2.5.0
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