[PATCH v2 0/6] Support getting default values from any control

[PATCH v2 0/6] Support getting default values from any control

[Ricardo Ribalda Delgado]

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_v5



Changelog v2 (compared to Support getting default values from any control

Rebase to latest version
Remove saa7164-* patches (Hans already ported them to v4l2-ctrl)
Update doc dates

Suggested by Laurent Pinchart <laurent.pinchart@ideasonboard.com>:

Fixes for the uvc implementation (error in lock handling) (Thanks!)


Changelog v1 (compared to v5 of New ioct VIDIOC_G_DEF_EXT_CTRLS):

Suggested by Hans Verkuil <hverkuil@xs4all.nl>:

Replace ioctl implementation with a new union on the struct v4l2_ext_controls
THANKS!

Ricardo Ribalda Delgado (6):
  videodev2.h: Extend struct v4l2_ext_controls
  media/core: Replace ctrl_class with which
  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
  Docbook: media: Document changes on struct v4l2_ext_controls

 Documentation/DocBook/media/v4l/v4l2.xml           | 10 ++++
 .../DocBook/media/v4l/vidioc-g-ext-ctrls.xml       | 28 +++++++++--
 drivers/media/platform/s5p-mfc/s5p_mfc_dec.c       |  2 +-
 drivers/media/platform/s5p-mfc/s5p_mfc_enc.c       |  2 +-
 drivers/media/usb/pvrusb2/pvrusb2-v4l2.c           | 16 ++++++-
 drivers/media/usb/uvc/uvc_v4l2.c                   | 20 ++++++++
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c      |  6 +--
 drivers/media/v4l2-core/v4l2-ctrls.c               | 54 ++++++++++++++++------
 drivers/media/v4l2-core/v4l2-ioctl.c               | 14 +++---
 include/uapi/linux/videodev2.h                     | 12 ++++-
 10 files changed, 131 insertions(+), 33 deletions(-)

-- 
2.6.1

[PATCH v2 1/6] videodev2.h: Extend struct v4l2_ext_controls

[Ricardo Ribalda Delgado]

So it can be used to get the default value of a control.

Without this change it is not possible to get  get the
default value of array controls.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 include/uapi/linux/videodev2.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index a0e87d16b726..4d88ee2d268e 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -1476,7 +1476,10 @@ struct v4l2_ext_control {
 } __attribute__ ((packed));
 
 struct v4l2_ext_controls {
-	__u32 ctrl_class;
+	union {
+		__u32 ctrl_class;
+		__u32 which;
+	};
 	__u32 count;
 	__u32 error_idx;
 	__u32 reserved[2];
@@ -1487,6 +1490,8 @@ struct v4l2_ext_controls {
 #define V4L2_CTRL_ID2CLASS(id)    ((id) & 0x0fff0000UL)
 #define V4L2_CTRL_DRIVER_PRIV(id) (((id) & 0xffff) >= 0x1000)
 #define V4L2_CTRL_MAX_DIMS	  (4)
+#define V4L2_CTRL_WHICH_CUR_VAL   0
+#define V4L2_CTRL_WHICH_DEF_VAL   0x0f000000
 
 enum v4l2_ctrl_type {
 	V4L2_CTRL_TYPE_INTEGER	     = 1,
-- 
2.6.1

[PATCH v2 2/6] media/core: Replace ctrl_class with which

[Ricardo Ribalda Delgado]

Replace the obsolete field ctrl_class with "which".

Make sure it not used in future modules by commenting out the field with
ifndef __KERNEL_ .

The field cannot be simply removed because that would be change on the
kenel API to the userspace (and we don't like that).

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 .../DocBook/media/v4l/vidioc-g-ext-ctrls.xml       |  6 +++---
 drivers/media/platform/s5p-mfc/s5p_mfc_dec.c       |  2 +-
 drivers/media/platform/s5p-mfc/s5p_mfc_enc.c       |  2 +-
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c      |  6 +++---
 drivers/media/v4l2-core/v4l2-ctrls.c               | 24 +++++++++++-----------
 drivers/media/v4l2-core/v4l2-ioctl.c               | 14 ++++++-------
 include/uapi/linux/videodev2.h                     |  5 +++++
 7 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml
index 842536aae8b4..47f9fee91442 100644
--- a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml
@@ -61,7 +61,7 @@ must belong to the same control class.</para>
 
     <para>Applications must always fill in the
 <structfield>count</structfield>,
-<structfield>ctrl_class</structfield>,
+<structfield>which</structfield>,
 <structfield>controls</structfield> and
 <structfield>reserved</structfield> fields of &v4l2-ext-controls;, and
 initialize the &v4l2-ext-control; array pointed to by the
@@ -109,7 +109,7 @@ the driver whether wrong values are automatically adjusted to a valid
 value or if an error is returned.</para>
 
     <para>When the <structfield>id</structfield> or
-<structfield>ctrl_class</structfield> is invalid drivers return an
+<structfield>which</structfield> is invalid drivers return an
 &EINVAL;. When the value is out of bounds drivers can choose to take
 the closest valid value or return an &ERANGE;, whatever seems more
 appropriate. In the first case the new value is set in
@@ -390,7 +390,7 @@ These controls are described in <xref linkend="rf-tuner-controls" />.</entry>
 	<listitem>
 	  <para>The &v4l2-ext-control; <structfield>id</structfield>
 is invalid, the &v4l2-ext-controls;
-<structfield>ctrl_class</structfield> is invalid, or the &v4l2-ext-control;
+<structfield>which</structfield> is invalid, or the &v4l2-ext-control;
 <structfield>value</structfield> was inappropriate (e.g. the given menu
 index is not supported by the driver). This error code is
 also returned by the <constant>VIDIOC_S_EXT_CTRLS</constant> and
diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
index 8c5060a7534f..1c4998c221a2 100644
--- a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
@@ -1119,7 +1119,7 @@ const struct v4l2_ioctl_ops *get_dec_v4l2_ioctl_ops(void)
 	return &s5p_mfc_dec_ioctl_ops;
 }
 
-#define IS_MFC51_PRIV(x) ((V4L2_CTRL_ID2CLASS(x) == V4L2_CTRL_CLASS_MPEG) \
+#define IS_MFC51_PRIV(x) ((V4L2_CTRL_ID2WHICH(x) == V4L2_CTRL_CLASS_MPEG) \
 						&& V4L2_CTRL_DRIVER_PRIV(x))
 
 int s5p_mfc_dec_ctrls_setup(struct s5p_mfc_ctx *ctx)
diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c b/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c
index 5c678ec9c9f2..115b7dac1d4c 100644
--- a/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c
@@ -2067,7 +2067,7 @@ const struct v4l2_ioctl_ops *get_enc_v4l2_ioctl_ops(void)
 	return &s5p_mfc_enc_ioctl_ops;
 }
 
-#define IS_MFC51_PRIV(x) ((V4L2_CTRL_ID2CLASS(x) == V4L2_CTRL_CLASS_MPEG) \
+#define IS_MFC51_PRIV(x) ((V4L2_CTRL_ID2WHICH(x) == V4L2_CTRL_CLASS_MPEG) \
 						&& V4L2_CTRL_DRIVER_PRIV(x))
 
 int s5p_mfc_enc_ctrls_setup(struct s5p_mfc_ctx *ctx)
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 327e83ac2469..8fd84a67478a 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -630,7 +630,7 @@ static inline int put_v4l2_input32(struct v4l2_input *kp, struct v4l2_input32 __
 }
 
 struct v4l2_ext_controls32 {
-	__u32 ctrl_class;
+	__u32 which;
 	__u32 count;
 	__u32 error_idx;
 	__u32 reserved[2];
@@ -673,7 +673,7 @@ static int get_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct v4l2_ext
 	compat_caddr_t p;
 
 	if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_ext_controls32)) ||
-		get_user(kp->ctrl_class, &up->ctrl_class) ||
+		get_user(kp->which, &up->which) ||
 		get_user(kp->count, &up->count) ||
 		get_user(kp->error_idx, &up->error_idx) ||
 		copy_from_user(kp->reserved, up->reserved,
@@ -723,7 +723,7 @@ static int put_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct v4l2_ext
 	compat_caddr_t p;
 
 	if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_ext_controls32)) ||
-		put_user(kp->ctrl_class, &up->ctrl_class) ||
+		put_user(kp->which, &up->which) ||
 		put_user(kp->count, &up->count) ||
 		put_user(kp->error_idx, &up->error_idx) ||
 		copy_to_user(up->reserved, kp->reserved, sizeof(up->reserved)))
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 4a1d9fdd14bb..cf8388407d68 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1762,7 +1762,7 @@ static struct v4l2_ctrl_ref *find_private_ref(
 	list_for_each_entry(ref, &hdl->ctrl_refs, node) {
 		/* Search for private user controls that are compatible with
 		   VIDIOC_G/S_CTRL. */
-		if (V4L2_CTRL_ID2CLASS(ref->ctrl->id) == V4L2_CTRL_CLASS_USER &&
+		if (V4L2_CTRL_ID2WHICH(ref->ctrl->id) == V4L2_CTRL_CLASS_USER &&
 		    V4L2_CTRL_DRIVER_PRIV(ref->ctrl->id)) {
 			if (!ref->ctrl->is_int)
 				continue;
@@ -1831,7 +1831,7 @@ static int handler_new_ref(struct v4l2_ctrl_handler *hdl,
 	struct v4l2_ctrl_ref *ref;
 	struct v4l2_ctrl_ref *new_ref;
 	u32 id = ctrl->id;
-	u32 class_ctrl = V4L2_CTRL_ID2CLASS(id) | 1;
+	u32 class_ctrl = V4L2_CTRL_ID2WHICH(id) | 1;
 	int bucket = id % hdl->nr_of_buckets;	/* which bucket to use */
 
 	/*
@@ -2253,9 +2253,9 @@ EXPORT_SYMBOL(v4l2_ctrl_add_handler);
 
 bool v4l2_ctrl_radio_filter(const struct v4l2_ctrl *ctrl)
 {
-	if (V4L2_CTRL_ID2CLASS(ctrl->id) == V4L2_CTRL_CLASS_FM_TX)
+	if (V4L2_CTRL_ID2WHICH(ctrl->id) == V4L2_CTRL_CLASS_FM_TX)
 		return true;
-	if (V4L2_CTRL_ID2CLASS(ctrl->id) == V4L2_CTRL_CLASS_FM_RX)
+	if (V4L2_CTRL_ID2WHICH(ctrl->id) == V4L2_CTRL_CLASS_FM_RX)
 		return true;
 	switch (ctrl->id) {
 	case V4L2_CID_AUDIO_MUTE:
@@ -2710,7 +2710,7 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
 
 		cs->error_idx = i;
 
-		if (cs->ctrl_class && V4L2_CTRL_ID2CLASS(id) != cs->ctrl_class)
+		if (cs->which && V4L2_CTRL_ID2WHICH(id) != cs->which)
 			return -EINVAL;
 
 		/* Old-style private controls are not allowed for
@@ -2787,11 +2787,11 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
 /* Handles the corner case where cs->count == 0. It checks whether the
    specified control class exists. If that class ID is 0, then it checks
    whether there are any controls at all. */
-static int class_check(struct v4l2_ctrl_handler *hdl, u32 ctrl_class)
+static int class_check(struct v4l2_ctrl_handler *hdl, u32 which)
 {
-	if (ctrl_class == 0)
+	if (!which)
 		return list_empty(&hdl->ctrl_refs) ? -EINVAL : 0;
-	return find_ref_lock(hdl, ctrl_class | 1) ? 0 : -EINVAL;
+	return find_ref_lock(hdl, which | 1) ? 0 : -EINVAL;
 }
 
 
@@ -2805,13 +2805,13 @@ int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *cs
 	int i, j;
 
 	cs->error_idx = cs->count;
-	cs->ctrl_class = V4L2_CTRL_ID2CLASS(cs->ctrl_class);
+	cs->which = V4L2_CTRL_ID2WHICH(cs->which);
 
 	if (hdl == NULL)
 		return -EINVAL;
 
 	if (cs->count == 0)
-		return class_check(hdl, cs->ctrl_class);
+		return class_check(hdl, cs->which);
 
 	if (cs->count > ARRAY_SIZE(helper)) {
 		helpers = kmalloc_array(cs->count, sizeof(helper[0]),
@@ -3064,13 +3064,13 @@ static int try_set_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
 	int ret;
 
 	cs->error_idx = cs->count;
-	cs->ctrl_class = V4L2_CTRL_ID2CLASS(cs->ctrl_class);
+	cs->which = V4L2_CTRL_ID2WHICH(cs->which);
 
 	if (hdl == NULL)
 		return -EINVAL;
 
 	if (cs->count == 0)
-		return class_check(hdl, cs->ctrl_class);
+		return class_check(hdl, cs->which);
 
 	if (cs->count > ARRAY_SIZE(helper)) {
 		helpers = kmalloc_array(cs->count, sizeof(helper[0]),
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 7486af2c8ae4..8a018c6dd16a 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -565,8 +565,8 @@ static void v4l_print_ext_controls(const void *arg, bool write_only)
 	const struct v4l2_ext_controls *p = arg;
 	int i;
 
-	pr_cont("class=0x%x, count=%d, error_idx=%d",
-			p->ctrl_class, p->count, p->error_idx);
+	pr_cont("which=0x%x, count=%d, error_idx=%d",
+			p->which, p->count, p->error_idx);
 	for (i = 0; i < p->count; i++) {
 		if (!p->controls[i].size)
 			pr_cont(", id/val=0x%x/0x%x",
@@ -902,13 +902,13 @@ static int check_ext_ctrls(struct v4l2_ext_controls *c, int allow_priv)
 	   Only when passed in through VIDIOC_G_CTRL and VIDIOC_S_CTRL
 	   is it allowed for backwards compatibility.
 	 */
-	if (!allow_priv && c->ctrl_class == V4L2_CID_PRIVATE_BASE)
+	if (!allow_priv && c->which == V4L2_CID_PRIVATE_BASE)
 		return 0;
-	if (c->ctrl_class == 0)
+	if (!c->which)
 		return 1;
 	/* Check that all controls are from the same control class. */
 	for (i = 0; i < c->count; i++) {
-		if (V4L2_CTRL_ID2CLASS(c->controls[i].id) != c->ctrl_class) {
+		if (V4L2_CTRL_ID2WHICH(c->controls[i].id) != c->which) {
 			c->error_idx = i;
 			return 0;
 		}
@@ -1969,7 +1969,7 @@ static int v4l_g_ctrl(const struct v4l2_ioctl_ops *ops,
 	if (ops->vidioc_g_ext_ctrls == NULL)
 		return -ENOTTY;
 
-	ctrls.ctrl_class = V4L2_CTRL_ID2CLASS(p->id);
+	ctrls.which = V4L2_CTRL_ID2WHICH(p->id);
 	ctrls.count = 1;
 	ctrls.controls = &ctrl;
 	ctrl.id = p->id;
@@ -2003,7 +2003,7 @@ static int v4l_s_ctrl(const struct v4l2_ioctl_ops *ops,
 	if (ops->vidioc_s_ext_ctrls == NULL)
 		return -ENOTTY;
 
-	ctrls.ctrl_class = V4L2_CTRL_ID2CLASS(p->id);
+	ctrls.which = V4L2_CTRL_ID2WHICH(p->id);
 	ctrls.count = 1;
 	ctrls.controls = &ctrl;
 	ctrl.id = p->id;
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 4d88ee2d268e..bd2dc9431ac1 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -1477,7 +1477,9 @@ struct v4l2_ext_control {
 
 struct v4l2_ext_controls {
 	union {
+#ifndef __KERNEL__
 		__u32 ctrl_class;
+#endif
 		__u32 which;
 	};
 	__u32 count;
@@ -1487,7 +1489,10 @@ struct v4l2_ext_controls {
 };
 
 #define V4L2_CTRL_ID_MASK      	  (0x0fffffff)
+#ifndef __KERNEL__
 #define V4L2_CTRL_ID2CLASS(id)    ((id) & 0x0fff0000UL)
+#endif
+#define V4L2_CTRL_ID2WHICH(id)    ((id) & 0x0fff0000UL)
 #define V4L2_CTRL_DRIVER_PRIV(id) (((id) & 0xffff) >= 0x1000)
 #define V4L2_CTRL_MAX_DIMS	  (4)
 #define V4L2_CTRL_WHICH_CUR_VAL   0
-- 
2.6.1

[PATCH v2 3/6] media/v4l2-core: struct struct v4l2_ext_controls param which

[Ricardo Ribalda Delgado]

Support for new field which on v4l2_ext_controls, used to get the
default value of one or more controls.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 drivers/media/v4l2-core/v4l2-ctrls.c | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index cf8388407d68..5216a00b2b16 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1491,6 +1491,17 @@ static int new_to_user(struct v4l2_ext_control *c,
 	return ptr_to_user(c, ctrl, ctrl->p_new);
 }
 
+/* Helper function: copy the initial control value back to the caller */
+static int def_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
+{
+	int idx;
+
+	for (idx = 0; idx < ctrl->elems; idx++)
+		ctrl->type_ops->init(ctrl, idx, ctrl->p_new);
+
+	return ptr_to_user(c, ctrl, ctrl->p_new);
+}
+
 /* Helper function: copy the caller-provider value to the given control value */
 static int user_to_ptr(struct v4l2_ext_control *c,
 		       struct v4l2_ctrl *ctrl,
@@ -2710,7 +2721,9 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
 
 		cs->error_idx = i;
 
-		if (cs->which && V4L2_CTRL_ID2WHICH(id) != cs->which)
+		if (cs->which &&
+		    cs->which != V4L2_CTRL_WHICH_DEF_VAL &&
+		    V4L2_CTRL_ID2WHICH(id) != cs->which)
 			return -EINVAL;
 
 		/* Old-style private controls are not allowed for
@@ -2789,7 +2802,7 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
    whether there are any controls at all. */
 static int class_check(struct v4l2_ctrl_handler *hdl, u32 which)
 {
-	if (!which)
+	if (which == 0 || which == V4L2_CTRL_WHICH_DEF_VAL)
 		return list_empty(&hdl->ctrl_refs) ? -EINVAL : 0;
 	return find_ref_lock(hdl, which | 1) ? 0 : -EINVAL;
 }
@@ -2803,6 +2816,9 @@ int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *cs
 	struct v4l2_ctrl_helper *helpers = helper;
 	int ret;
 	int i, j;
+	bool def_value;
+
+	def_value = (cs->which == V4L2_CTRL_WHICH_DEF_VAL);
 
 	cs->error_idx = cs->count;
 	cs->which = V4L2_CTRL_ID2WHICH(cs->which);
@@ -2829,9 +2845,11 @@ int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *cs
 
 	for (i = 0; !ret && i < cs->count; i++) {
 		int (*ctrl_to_user)(struct v4l2_ext_control *c,
-				    struct v4l2_ctrl *ctrl) = cur_to_user;
+				    struct v4l2_ctrl *ctrl);
 		struct v4l2_ctrl *master;
 
+		ctrl_to_user = def_value ? def_to_user : cur_to_user;
+
 		if (helpers[i].mref == NULL)
 			continue;
 
@@ -2841,8 +2859,9 @@ int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *cs
 		v4l2_ctrl_lock(master);
 
 		/* g_volatile_ctrl will update the new control values */
-		if ((master->flags & V4L2_CTRL_FLAG_VOLATILE) ||
-			(master->has_volatiles && !is_cur_manual(master))) {
+		if (!def_value &&
+		    ((master->flags & V4L2_CTRL_FLAG_VOLATILE) ||
+		    (master->has_volatiles && !is_cur_manual(master)))) {
 			for (j = 0; j < master->ncontrols; j++)
 				cur_to_new(master->cluster[j]);
 			ret = call_op(master, g_volatile_ctrl);
@@ -3064,6 +3083,11 @@ static int try_set_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
 	int ret;
 
 	cs->error_idx = cs->count;
+
+	/* Default value cannot be changed */
+	if (cs->which == V4L2_CTRL_WHICH_DEF_VAL)
+		return -EINVAL;
+
 	cs->which = V4L2_CTRL_ID2WHICH(cs->which);
 
 	if (hdl == NULL)
-- 
2.6.1

[PATCH v2 4/6] usb/uvc: Support for V4L2_CTRL_WHICH_DEF_VAL

[Ricardo Ribalda Delgado]

This driver does not use the control infrastructure.
Add support for the new field which on structure
 v4l2_ext_controls

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 drivers/media/usb/uvc/uvc_v4l2.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 2764f43607c1..d7723ce772b3 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -983,6 +983,22 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh,
 	unsigned int i;
 	int ret;
 
+	if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {
+		for (i = 0; i < ctrls->count; ++ctrl, ++i) {
+			struct v4l2_queryctrl qc = { .id = ctrl->id };
+
+			ret = uvc_query_v4l2_ctrl(chain, &qc);
+			if (ret < 0) {
+				ctrls->error_idx = i;
+				return ret;
+			}
+
+			ctrl->value = qc.default_value;
+		}
+
+		return 0;
+	}
+
 	ret = uvc_ctrl_begin(chain);
 	if (ret < 0)
 		return ret;
@@ -1010,6 +1026,10 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle,
 	unsigned int i;
 	int ret;
 
+	/* Default value cannot be changed */
+	if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL)
+		return -EINVAL;
+
 	ret = uvc_ctrl_begin(chain);
 	if (ret < 0)
 		return ret;
-- 
2.6.1

[PATCH v2 5/6] media/usb/pvrusb2: Support for V4L2_CTRL_WHICH_DEF_VAL

[Ricardo Ribalda Delgado]

This driver does not use the control infrastructure.
Add support for the new field which on structure
 v4l2_ext_controls

Acked-by: Mike Isely <isely@pobox.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 drivers/media/usb/pvrusb2/pvrusb2-v4l2.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
index 1c5f85bf7ed4..81f788b7b242 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
@@ -628,6 +628,7 @@ static int pvr2_g_ext_ctrls(struct file *file, void *priv,
 	struct pvr2_v4l2_fh *fh = file->private_data;
 	struct pvr2_hdw *hdw = fh->channel.mc_head->hdw;
 	struct v4l2_ext_control *ctrl;
+	struct pvr2_ctrl *cptr;
 	unsigned int idx;
 	int val;
 	int ret;
@@ -635,8 +636,15 @@ static int pvr2_g_ext_ctrls(struct file *file, void *priv,
 	ret = 0;
 	for (idx = 0; idx < ctls->count; idx++) {
 		ctrl = ctls->controls + idx;
-		ret = pvr2_ctrl_get_value(
-				pvr2_hdw_get_ctrl_v4l(hdw, ctrl->id), &val);
+		cptr = pvr2_hdw_get_ctrl_v4l(hdw, ctrl->id);
+		if (cptr) {
+			if (ctls->which == V4L2_CTRL_WHICH_DEF_VAL)
+				pvr2_ctrl_get_def(cptr, &val);
+			else
+				ret = pvr2_ctrl_get_value(cptr, &val);
+		} else
+			ret = -EINVAL;
+
 		if (ret) {
 			ctls->error_idx = idx;
 			return ret;
@@ -658,6 +666,10 @@ static int pvr2_s_ext_ctrls(struct file *file, void *priv,
 	unsigned int idx;
 	int ret;
 
+	/* Default value cannot be changed */
+	if (ctls->which == V4L2_CTRL_WHICH_DEF_VAL)
+		return -EINVAL;
+
 	ret = 0;
 	for (idx = 0; idx < ctls->count; idx++) {
 		ctrl = ctls->controls + idx;
-- 
2.6.1

[PATCH v2 6/6] Docbook: media: Document changes on struct v4l2_ext_controls

[Ricardo Ribalda Delgado]

Vidioc-g-ext-ctrls can now be used to get the default value of the
controls.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 Documentation/DocBook/media/v4l/v4l2.xml           | 10 ++++++++++
 .../DocBook/media/v4l/vidioc-g-ext-ctrls.xml       | 22 ++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml
index 7e61643358de..42e626d6c936 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -152,6 +152,16 @@ structs, ioctls) must be noted in more detail in the history chapter
 (compat.xml), along with the possible impact on existing drivers and
 applications. -->
       <revision>
+	<revnumber>4.5</revnumber>
+	<date>2015-10-29</date>
+	<authorinitials>rr</authorinitials>
+	<revremark>Extend vidioc-g-ext-ctrls;. Replace ctrl_class with a new
+union with ctrl_class and which. Which is used to select the current value of
+the control or the default value.
+	</revremark>
+      </revision>
+
+      <revision>
 	<revnumber>4.4</revnumber>
 	<date>2015-05-26</date>
 	<authorinitials>ap</authorinitials>
diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml
index 47f9fee91442..eb82f7e7d06b 100644
--- a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml
@@ -223,7 +223,12 @@ Valid if <constant>V4L2_CTRL_FLAG_HAS_PAYLOAD</constant> is set for this control
       <tgroup cols="3">
 	&cs-str;
 	<tbody valign="top">
+	 <row>
+	    <entry>union</entry>
+	    <entry>(anonymous)</entry>
+	  </row>
 	  <row>
+	    <entry></entry>
 	    <entry>__u32</entry>
 	    <entry><structfield>ctrl_class</structfield></entry>
 	    <entry>The control class to which all controls belong, see
@@ -235,6 +240,23 @@ with a <structfield>count</structfield> of 0. If that succeeds, then the driver
 supports this feature.</entry>
 	  </row>
 	  <row>
+	    <entry></entry>
+	    <entry>__u32</entry>
+	    <entry><structfield>which</structfield></entry>
+	    <entry><para>Which value of the control to get/set/try. <constant>V4L2_CTRL_WHICH_CUR_VAL</constant>
+will return the current value of the control and <constant>V4L2_CTRL_WHICH_DEF_VAL</constant> will
+return the default value of the control. Please note that you can only get the default value of the
+control, you cannot set or try it.</para>
+<para>For backwards compatibility you can also use a control class here (see
+<xref linkend="ctrl-class" />). In that case all controls have to belong to that
+control class. This usage is deprecated, instead just use <constant>V4L2_CTRL_WHICH_CUR_VAL</constant>.
+There are some very old drivers that do not yet support <constant>V4L2_CTRL_WHICH_CUR_VAL</constant>
+and that require a control class here. You can test for such drivers by setting ctrl_class to
+<constant>V4L2_CTRL_WHICH_CUR_VAL</constant> and calling VIDIOC_TRY_EXT_CTRLS with a count of 0.
+If that fails, then the driver does not support <constant>V4L2_CTRL_WHICH_CUR_VAL</constant>.</para>
+</entry>
+	  </row>
+	  <row>
 	    <entry>__u32</entry>
 	    <entry><structfield>count</structfield></entry>
 	    <entry>The number of controls in the controls array. May
-- 
2.6.1

Re: [PATCH v2 5/6] media/usb/pvrusb2: Support for V4L2_CTRL_WHICH_DEF_VAL

[Mike Isely]

Looks good to me (still), including now the change I had previously 
suggested.  For the record, the ack still applies.  (I guess you can 
consider this to be an ack of the ack...)

  -Mike


On Thu, 29 Oct 2015, Ricardo Ribalda Delgado wrote:

> This driver does not use the control infrastructure.
> Add support for the new field which on structure
>  v4l2_ext_controls
> 
> Acked-by: Mike Isely <isely@pobox.com>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> ---
>  drivers/media/usb/pvrusb2/pvrusb2-v4l2.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
> index 1c5f85bf7ed4..81f788b7b242 100644
> --- a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
> +++ b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
> @@ -628,6 +628,7 @@ static int pvr2_g_ext_ctrls(struct file *file, void *priv,
>  	struct pvr2_v4l2_fh *fh = file->private_data;
>  	struct pvr2_hdw *hdw = fh->channel.mc_head->hdw;
>  	struct v4l2_ext_control *ctrl;
> +	struct pvr2_ctrl *cptr;
>  	unsigned int idx;
>  	int val;
>  	int ret;
> @@ -635,8 +636,15 @@ static int pvr2_g_ext_ctrls(struct file *file, void *priv,
>  	ret = 0;
>  	for (idx = 0; idx < ctls->count; idx++) {
>  		ctrl = ctls->controls + idx;
> -		ret = pvr2_ctrl_get_value(
> -				pvr2_hdw_get_ctrl_v4l(hdw, ctrl->id), &val);
> +		cptr = pvr2_hdw_get_ctrl_v4l(hdw, ctrl->id);
> +		if (cptr) {
> +			if (ctls->which == V4L2_CTRL_WHICH_DEF_VAL)
> +				pvr2_ctrl_get_def(cptr, &val);
> +			else
> +				ret = pvr2_ctrl_get_value(cptr, &val);
> +		} else
> +			ret = -EINVAL;
> +
>  		if (ret) {
>  			ctls->error_idx = idx;
>  			return ret;
> @@ -658,6 +666,10 @@ static int pvr2_s_ext_ctrls(struct file *file, void *priv,
>  	unsigned int idx;
>  	int ret;
>  
> +	/* Default value cannot be changed */
> +	if (ctls->which == V4L2_CTRL_WHICH_DEF_VAL)
> +		return -EINVAL;
> +
>  	ret = 0;
>  	for (idx = 0; idx < ctls->count; idx++) {
>  		ctrl = ctls->controls + idx;
> 

-- 

Mike Isely
isely @ isely (dot) net
PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8

Re: [PATCH v2 4/6] usb/uvc: Support for V4L2_CTRL_WHICH_DEF_VAL

[Laurent Pinchart]

Hi Ricardo,

Thank you for the patch.

On Thursday 29 October 2015 11:10:30 Ricardo Ribalda Delgado wrote:
> This driver does not use the control infrastructure.
> Add support for the new field which on structure
>  v4l2_ext_controls
> 
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/usb/uvc/uvc_v4l2.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c
> b/drivers/media/usb/uvc/uvc_v4l2.c index 2764f43607c1..d7723ce772b3 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -983,6 +983,22 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file,
> void *fh, unsigned int i;
>  	int ret;
> 
> +	if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {
> +		for (i = 0; i < ctrls->count; ++ctrl, ++i) {
> +			struct v4l2_queryctrl qc = { .id = ctrl->id };
> +
> +			ret = uvc_query_v4l2_ctrl(chain, &qc);
> +			if (ret < 0) {
> +				ctrls->error_idx = i;
> +				return ret;
> +			}
> +
> +			ctrl->value = qc.default_value;
> +		}
> +
> +		return 0;
> +	}
> +
>  	ret = uvc_ctrl_begin(chain);
>  	if (ret < 0)
>  		return ret;
> @@ -1010,6 +1026,10 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh
> *handle, unsigned int i;
>  	int ret;
> 
> +	/* Default value cannot be changed */
> +	if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL)
> +		return -EINVAL;
> +
>  	ret = uvc_ctrl_begin(chain);
>  	if (ret < 0)
>  		return ret;

-- 
Regards,

Laurent Pinchart