Hi Laurent,
Thanks for the review. As soon as the second patch has also been reviewed,
I'll work on both of them.
Thanks
Guennadi
On Fri, 23 Mar 2018, Laurent Pinchart wrote:
> Hi Guennadi,
>
> Thank you for the patch.
>
> On Friday, 23 March 2018 11:24:00 EET Laurent Pinchart wrote:
> > From: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> >
> > UVC defines a method of handling asynchronous controls, which sends a
> > USB packet over the interrupt pipe. This patch implements support for
> > such packets by sending a control event to the user. Since this can
> > involve USB traffic and, therefore, scheduling, this has to be done
> > in a work queue.
> >
> > Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@xxxxxxxxx>
> > ---
> > drivers/media/usb/uvc/uvc_ctrl.c | 166 ++++++++++++++++++++++++++++++----
> > drivers/media/usb/uvc/uvc_status.c | 111 ++++++++++++++++++++++---
> > drivers/media/usb/uvc/uvc_v4l2.c | 4 +-
> > drivers/media/usb/uvc/uvcvideo.h | 15 +++-
> > include/uapi/linux/uvcvideo.h | 2 +
> > 5 files changed, 269 insertions(+), 29 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c
> > b/drivers/media/usb/uvc/uvc_ctrl.c index 4042cbdb721b..f4773c56438c 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -20,6 +20,7 @@
> > #include <linux/videodev2.h>
> > #include <linux/vmalloc.h>
> > #include <linux/wait.h>
> > +#include <linux/workqueue.h>
> > #include <linux/atomic.h>
> > #include <media/v4l2-ctrls.h>
> >
> > @@ -1222,30 +1223,134 @@ static void uvc_ctrl_send_event(struct uvc_fh
> > *handle, {
> > struct v4l2_subscribed_event *sev;
> > struct v4l2_event ev;
> > + bool autoupdate;
> >
> > if (list_empty(&mapping->ev_subs))
> > return;
> >
> > + if (!handle) {
>
> In which circumstances does this happen ? Is it when the device reports a
> control change event without an prior control set ? Have you seen that
> happening in practice ?
>
> > + autoupdate = true;
> > + sev = list_first_entry(&mapping->ev_subs,
> > + struct v4l2_subscribed_event, node);
> > + handle = container_of(sev->fh, struct uvc_fh, vfh);
>
> There's a check below that guards against sev->fh being NULL. Could sev->fh be
> NULL here ?
>
> > + } else {
> > + autoupdate = false;
> > + }
> > +
> > uvc_ctrl_fill_event(handle->chain, &ev, ctrl, mapping, value, changes);
> >
> > list_for_each_entry(sev, &mapping->ev_subs, node) {
> > if (sev->fh && (sev->fh != &handle->vfh ||
> > (sev->flags & V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK) ||
> > - (changes & V4L2_EVENT_CTRL_CH_FLAGS)))
> > + (changes & V4L2_EVENT_CTRL_CH_FLAGS) || autoupdate))
> > v4l2_event_queue_fh(sev->fh, &ev);
> > }
> > }
> >
> > -static void uvc_ctrl_send_slave_event(struct uvc_fh *handle,
> > - struct uvc_control *master, u32 slave_id,
> > - const struct v4l2_ext_control *xctrls, unsigned int xctrls_count)
> > +static void __uvc_ctrl_send_slave_event(struct uvc_fh *handle,
> > + struct uvc_control *master, u32 slave_id)
> > {
> > struct uvc_control_mapping *mapping = NULL;
> > struct uvc_control *ctrl = NULL;
> > u32 changes = V4L2_EVENT_CTRL_CH_FLAGS;
> > - unsigned int i;
> > s32 val = 0;
> >
> > + __uvc_find_control(master->entity, slave_id, &mapping, &ctrl, 0);
> > + if (ctrl == NULL)
> > + return;
> > +
> > + if (__uvc_ctrl_get(handle->chain, ctrl, mapping, &val) == 0)
> > + changes |= V4L2_EVENT_CTRL_CH_VALUE;
> > +
> > + uvc_ctrl_send_event(handle, ctrl, mapping, val, changes);
> > +}
> > +
> > +static void uvc_ctrl_status_event_work(struct work_struct *work)
> > +{
> > + struct uvc_device *dev = container_of(work, struct uvc_device,
> > + async_ctrl.work);
> > + struct uvc_video_chain *chain;
> > + struct uvc_ctrl_work *w = &dev->async_ctrl;
> > + struct uvc_control_mapping *mapping;
> > + struct uvc_control *ctrl;
> > + struct uvc_fh *handle;
> > + unsigned int i;
> > + u8 *data;
> > +
> > + spin_lock_irq(&w->lock);
> > + data = w->data;
> > + w->data = NULL;
> > + chain = w->chain;
> > + ctrl = w->ctrl;
> > + handle = ctrl->handle;
> > + ctrl->handle = NULL;
> > + spin_unlock_irq(&w->lock);
> > +
> > + if (mutex_lock_interruptible(&chain->ctrl_mutex))
> > + goto free;
>
> This will result in the event being lost, which isn't very nice (see below for
> additional comments on this topic). Can't we use mutex_lock() ?
>
> > +
> > + list_for_each_entry(mapping, &ctrl->info.mappings, list) {
> > + s32 value = mapping->get(mapping, UVC_GET_CUR, data);
> > +
> > + for (i = 0; i < ARRAY_SIZE(mapping->slave_ids); ++i) {
> > + if (!mapping->slave_ids[i])
> > + break;
> > +
> > + __uvc_ctrl_send_slave_event(handle, ctrl,
> > + mapping->slave_ids[i]);
> > + }
> > +
> > + if (mapping->v4l2_type == V4L2_CTRL_TYPE_MENU) {
> > + struct uvc_menu_info *menu = mapping->menu_info;
> > + unsigned int i;
> > +
> > + for (i = 0; i < mapping->menu_count; ++i, ++menu)
> > + if (menu->value == value) {
> > + value = i;
> > + break;
> > + }
> > + }
>
> Would this be useful to move the mapping->get() and menu control handling code
> out of __uvc_ctrl_get() into a __uvc_ctrl_get_value() function and call it
> here ?
>
> > + uvc_ctrl_send_event(handle, ctrl, mapping, value,
> > + V4L2_EVENT_CTRL_CH_VALUE);
> > + }
> > +
> > + mutex_unlock(&chain->ctrl_mutex);
> > +
> > +free:
> > + kfree(data);
> > +}
> > +
> > +void uvc_ctrl_status_event(struct uvc_video_chain *chain,
> > + struct uvc_control *ctrl, u8 *data, size_t len)
> > +{
> > + struct uvc_device *dev = chain->dev;
> > + struct uvc_ctrl_work *w = &dev->async_ctrl;
> > +
> > + if (list_empty(&ctrl->info.mappings))
> > + return;
> > +
> > + spin_lock(&w->lock);
> > + if (w->data)
> > + /* A previous event work hasn't run yet, we lose 1 event */
> > + kfree(w->data);
>
> I really don't like losing events :/
>
> > + w->data = kmalloc(len, GFP_ATOMIC);
>
> GFP_ATOMIC allocation isn't very nice either.
>
> How about if we instead delayed resubmitting the status URB until the event is
> fully processed by the work queue ? That way we wouldn't lose events, we
> wouldn't need memory allocation in atomic context, and if the work queue
> becomes a bottleneck we could even queue multiple status URBs and easily add
> them to a list for processing by the work queue.
>
> > + if (w->data) {
> > + memcpy(w->data, data, len);
> > + w->chain = chain;
> > + w->ctrl = ctrl;
> > + schedule_work(&w->work);
> > + }
> > + spin_unlock(&w->lock);
> > +}
> > +
> > +static void uvc_ctrl_send_slave_event(struct uvc_fh *handle,
> > + struct uvc_control *master, u32 slave_id,
> > + const struct v4l2_ext_control *xctrls, unsigned int xctrls_count)
> > +{
> > + unsigned int i;
> > +
> > /*
> > * We can skip sending an event for the slave if the slave
> > * is being modified in the same transaction.
> > @@ -1255,14 +1360,7 @@ static void uvc_ctrl_send_slave_event(struct uvc_fh
> > *handle, return;
> > }
> >
> > - __uvc_find_control(master->entity, slave_id, &mapping, &ctrl, 0);
> > - if (ctrl == NULL)
> > - return;
> > -
> > - if (__uvc_ctrl_get(handle->chain, ctrl, mapping, &val) == 0)
> > - changes |= V4L2_EVENT_CTRL_CH_VALUE;
> > -
> > - uvc_ctrl_send_event(handle, ctrl, mapping, val, changes);
> > + __uvc_ctrl_send_slave_event(handle, master, slave_id);
> > }
> >
> > static void uvc_ctrl_send_events(struct uvc_fh *handle,
> > @@ -1277,6 +1375,10 @@ static void uvc_ctrl_send_events(struct uvc_fh
> > *handle, for (i = 0; i < xctrls_count; ++i) {
> > ctrl = uvc_find_control(handle->chain, xctrls[i].id, &mapping);
> >
> > + if (ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS)
> > + /* Notification will be sent from an Interrupt event */
>
> Nitpicking, could you add a period at the end of sentences to match the
> comment style in the driver ?
>
> > + continue;
> > +
> > for (j = 0; j < ARRAY_SIZE(mapping->slave_ids); ++j) {
> > if (!mapping->slave_ids[j])
> > break;
> > @@ -1472,9 +1574,10 @@ int uvc_ctrl_get(struct uvc_video_chain *chain,
> > return __uvc_ctrl_get(chain, ctrl, mapping, &xctrl->value);
> > }
> >
> > -int uvc_ctrl_set(struct uvc_video_chain *chain,
> > +int uvc_ctrl_set(struct uvc_fh *handle,
> > struct v4l2_ext_control *xctrl)
> > {
> > + struct uvc_video_chain *chain = handle->chain;
> > struct uvc_control *ctrl;
> > struct uvc_control_mapping *mapping;
> > s32 value;
> > @@ -1488,6 +1591,25 @@ int uvc_ctrl_set(struct uvc_video_chain *chain,
> > return -EINVAL;
> > if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR))
> > return -EACCES;
> > + if (ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS) {
> > + if (ctrl->handle)
> > + /*
> > + * We have already sent this control to the camera
> > + * recently and are currently waiting for a completion
> > + * notification. The camera might already have completed
> > + * its processing and is ready to accept a new control
> > + * or it's still busy processing. If we send a new
> > + * instance of this control now, in the former case the
> > + * camera will process this one too and we'll get
> > + * completions for both, but we will only deliver an
> > + * event for one of them back to the user. In the latter
> > + * case the camera will reply with a STALL. It's easier
> > + * and more reliable to return an error now and let the
> > + * user retry.
> > + */
> > + return -EBUSY;
> > + ctrl->handle = handle;
>
> This part worries me. If the control change event isn't received for any
> reason (such as a buggy device for instance, or uvc_ctrl_status_event() being
> called with the previous event not processed yet), the control will stay busy
> forever.
>
> I see two approaches to fix this. One would be to forward all received control
> change events to all file handles unconditionally and remove the handle field
> from the uvc_control structure. Another one would be to add a timeout, storing
> the time at which the control has been set in the uvc_control structure, and
> checking whether the time difference exceeds a fixed timeout here. We could
> also combine the two, replacing the handle field with a timestamp field.
>
> Please keep in mind if trying this out that simply storing jiffies as a
> timestamp might cause counter overflow issues if the control is set, no event
> is ever received, and a second control set happens much later after one (or
> multiple) jiffies wraparounds. We could end up returning -EBUSY incorrectly.
> That might not be a real issue given the size of the jiffies counter though,
> I'll let you double-check.
>
> > + }
> >
> > /* Clamp out of range values. */
> > switch (mapping->v4l2_type) {
> > @@ -1612,7 +1734,9 @@ static int uvc_ctrl_get_flags(struct uvc_device *dev,
> > | (data[0] & UVC_CONTROL_CAP_SET ?
> > UVC_CTRL_FLAG_SET_CUR : 0)
> > | (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
> > - UVC_CTRL_FLAG_AUTO_UPDATE : 0);
> > + UVC_CTRL_FLAG_AUTO_UPDATE : 0)
> > + | (data[0] & UVC_CONTROL_CAP_ASYNCHRONOUS ?
> > + UVC_CTRL_FLAG_ASYNCHRONOUS : 0);
> >
> > kfree(data);
> > return ret;
> > @@ -2158,6 +2282,13 @@ static void uvc_ctrl_init_ctrl(struct uvc_device
> > *dev, struct uvc_control *ctrl) if (!ctrl->initialized)
> > return;
> >
> > + /* Temporarily abuse DATA_CURRENT buffer to avoid 1 byte allocation */
> > + if (!uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id,
> > + dev->intfnum, info->selector,
> > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT), 1) &&
> > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT)[0] & 0x10)
> > + ctrl->info.flags |= UVC_CTRL_FLAG_ASYNCHRONOUS;
>
> I think this isn't needed anymore as the uvc_ctrl_add_info() function now
> calls uvc_ctrl_get_flags() to update the flags. Could you please confirm ?
>
> > for (; mapping < mend; ++mapping) {
> > if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
> > ctrl->info.selector == mapping->selector)
> > @@ -2173,6 +2304,9 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
> > struct uvc_entity *entity;
> > unsigned int i;
> >
> > + spin_lock_init(&dev->async_ctrl.lock);
> > + INIT_WORK(&dev->async_ctrl.work, uvc_ctrl_status_event_work);
> > +
> > /* Walk the entities list and instantiate controls */
> > list_for_each_entry(entity, &dev->entities, list) {
> > struct uvc_control *ctrl;
> > @@ -2241,6 +2375,8 @@ void uvc_ctrl_cleanup_device(struct uvc_device *dev)
> > struct uvc_entity *entity;
> > unsigned int i;
> >
> > + cancel_work_sync(&dev->async_ctrl.work);
> > +
> > /* Free controls and control mappings for all entities. */
> > list_for_each_entry(entity, &dev->entities, list) {
> > for (i = 0; i < entity->ncontrols; ++i) {
> > diff --git a/drivers/media/usb/uvc/uvc_status.c
> > b/drivers/media/usb/uvc/uvc_status.c index 7b710410584a..d1d83aed6a1d
> > 100644
> > --- a/drivers/media/usb/uvc/uvc_status.c
> > +++ b/drivers/media/usb/uvc/uvc_status.c
> > @@ -78,7 +78,24 @@ static void uvc_input_report_key(struct uvc_device *dev,
> > unsigned int code, /*
> > --------------------------------------------------------------------------
> > * Status interrupt endpoint
> > */
> > -static void uvc_event_streaming(struct uvc_device *dev, u8 *data, int len)
> > +struct uvc_streaming_status {
> > + u8 bStatusType;
> > + u8 bOriginator;
> > + u8 bEvent;
> > + u8 bValue[];
> > +} __packed;
> > +
> > +struct uvc_control_status {
> > + u8 bStatusType;
> > + u8 bOriginator;
> > + u8 bEvent;
> > + u8 bSelector;
> > + u8 bAttribute;
> > + u8 bValue[];
> > +} __packed;
> > +
> > +static void uvc_event_streaming(struct uvc_device *dev,
> > + struct uvc_streaming_status *status, int len)
> > {
> > if (len < 3) {
> > uvc_trace(UVC_TRACE_STATUS, "Invalid streaming status event "
> > @@ -86,31 +103,101 @@ static void uvc_event_streaming(struct uvc_device
> > *dev, u8 *data, int len) return;
> > }
> >
> > - if (data[2] == 0) {
> > + if (status->bEvent == 0) {
> > if (len < 4)
> > return;
> > uvc_trace(UVC_TRACE_STATUS, "Button (intf %u) %s len %d\n",
> > - data[1], data[3] ? "pressed" : "released", len);
> > - uvc_input_report_key(dev, KEY_CAMERA, data[3]);
> > + status->bOriginator,
> > + status->bValue[0] ? "pressed" : "released", len);
> > + uvc_input_report_key(dev, KEY_CAMERA, status->bValue[0]);
> > } else {
> > uvc_trace(UVC_TRACE_STATUS,
> > "Stream %u error event %02x len %d.\n",
> > - data[1], data[2], len);
> > + status->bOriginator, status->bEvent, len);
> > }
> > }
> >
> > -static void uvc_event_control(struct uvc_device *dev, u8 *data, int len)
> > +#define UVC_CTRL_VALUE_CHANGE 0
> > +#define UVC_CTRL_INFO_CHANGE 1
> > +#define UVC_CTRL_FAILURE_CHANGE 2
> > +#define UVC_CTRL_MIN_CHANGE 3
> > +#define UVC_CTRL_MAX_CHANGE 4
> > +
> > +static struct uvc_control *uvc_event_entity_ctrl(struct uvc_entity *entity,
> > + u8 selector)
>
> Should this be named uvc_event_entity_find_ctrl() ?
>
> > +{
> > + struct uvc_control *ctrl;
> > + unsigned int i;
> > +
> > + for (i = 0, ctrl = entity->controls; i < entity->ncontrols; i++, ctrl++)
> > + if (ctrl->info.selector == selector)
> > + return ctrl;
> > +
> > + return NULL;
> > +}
> > +
> > +static struct uvc_control *uvc_event_find_ctrl(struct uvc_device *dev,
> > + struct uvc_control_status *status,
> > + struct uvc_video_chain **chain)
> > +{
> > + list_for_each_entry((*chain), &dev->chains, list) {
>
> Do you need parentheses around *chain ?
>
> > + struct uvc_entity *entity;
> > + struct uvc_control *ctrl;
> > +
> > + list_for_each_entry(entity, &(*chain)->entities, chain) {
> > + if (entity->id == status->bOriginator) {
>
> If you invert the check here with
>
> if (entity->id == status->bOriginator)
> continue;
>
> you'll gain one level of indentation and you might be able to inline
> uvc_event_entity_ctrl(). Up to you.
>
> > + ctrl = uvc_event_entity_ctrl(entity,
> > + status->bSelector);
> > + /*
> > + * Some buggy cameras send asynchronous Control
> > + * Change events for control, other than the
> > + * ones, that had been changed, even though the
> > + * AutoUpdate flag isn't set for the control.
> > + */
>
> That's lots of commas, I'm not sure what you mean here. Are there cameras that
> send event for controls that haven't changed ? Or cameras that send events for
> controls that don't have the auto-update flag set ? Do you know what cameras
> are affected ?
>
> > + if (ctrl && (!ctrl->handle ||
> > + ctrl->handle->chain == *chain))
> > + return ctrl;
> > + }
> > + }
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > +static void uvc_event_control(struct uvc_device *dev,
> > + struct uvc_control_status *status, int len)
>
> While at it you can make the status pointer const.
>
> > {
> > - char *attrs[3] = { "value", "info", "failure" };
> > + struct uvc_video_chain *chain;
> > + struct uvc_control *ctrl;
> > + char *attrs[] = { "value", "info", "failure", "min", "max" };
>
> You can also make these static const (and while at it could you please move
> them before the other two variables ?).
>
> >
> > - if (len < 6 || data[2] != 0 || data[4] > 2) {
> > + if (len < 6 || status->bEvent != 0 ||
> > + status->bAttribute >= ARRAY_SIZE(attrs)) {
> > uvc_trace(UVC_TRACE_STATUS, "Invalid control status event "
> > "received.\n");
> > return;
>
> The min and max events are only defined in UVC 1.5 but I suppose there's no
> need to check for the UVC version here, it won't hurt to handle them on UVC
> 1.1 as well as they should not occur.
>
> > }
> >
> > uvc_trace(UVC_TRACE_STATUS, "Control %u/%u %s change len %d.\n",
> > - data[1], data[3], attrs[data[4]], len);
> > + status->bOriginator, status->bSelector,
> > + attrs[status->bAttribute], len);
> > +
> > + /* Find the control. */
> > + ctrl = uvc_event_find_ctrl(dev, status, &chain);
> > + if (!ctrl)
> > + return;
> > +
> > + switch (status->bAttribute) {
> > + case UVC_CTRL_VALUE_CHANGE:
> > + uvc_ctrl_status_event(chain, ctrl, status->bValue, len -
> > + offsetof(struct uvc_control_status, bValue));
> > + break;
>
> How about a blank line here ?
>
> > + case UVC_CTRL_INFO_CHANGE:
> > + case UVC_CTRL_FAILURE_CHANGE:
> > + case UVC_CTRL_MIN_CHANGE:
> > + case UVC_CTRL_MAX_CHANGE:
> > + break;
> > + }
> > }
> >
> > static void uvc_status_complete(struct urb *urb)
> > @@ -139,11 +226,13 @@ static void uvc_status_complete(struct urb *urb)
> > if (len > 0) {
> > switch (dev->status[0] & 0x0f) {
> > case UVC_STATUS_TYPE_CONTROL:
> > - uvc_event_control(dev, dev->status, len);
> > + uvc_event_control(dev,
> > + (struct uvc_control_status *)dev->status, len);
>
> Is dev->status guaranteed to be aligned properly so that no unaligned access
> fault can occur when dereferencing memory through the uvc_control_status and
> uvc_streaming_status structures ? Unaligned access are the reason why UVC
> descriptors are parsed manually instead of through a structure.
> > break;
> >
> > case UVC_STATUS_TYPE_STREAMING:
> > - uvc_event_streaming(dev, dev->status, len);
> > + uvc_event_streaming(dev,
> > + (struct uvc_streaming_status *)dev->status, len);
> > break;
> >
> > default:
> > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c
> > b/drivers/media/usb/uvc/uvc_v4l2.c index 818a4369a51a..55f973eb16eb 100644
> > --- a/drivers/media/usb/uvc/uvc_v4l2.c
> > +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> > @@ -994,7 +994,7 @@ static int uvc_ioctl_s_ctrl(struct file *file, void *fh,
> > if (ret < 0)
> > return ret;
> >
> > - ret = uvc_ctrl_set(chain, &xctrl);
> > + ret = uvc_ctrl_set(handle, &xctrl);
> > if (ret < 0) {
> > uvc_ctrl_rollback(handle);
> > return ret;
> > @@ -1069,7 +1069,7 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh
> > *handle, return ret;
> >
> > for (i = 0; i < ctrls->count; ++ctrl, ++i) {
> > - ret = uvc_ctrl_set(chain, ctrl);
> > + ret = uvc_ctrl_set(handle, ctrl);
> > if (ret < 0) {
> > uvc_ctrl_rollback(handle);
> > ctrls->error_idx = commit ? ctrls->count : i;
> > diff --git a/drivers/media/usb/uvc/uvcvideo.h
> > b/drivers/media/usb/uvc/uvcvideo.h index 6b955e0dd956..483182fe1b4d 100644
> > --- a/drivers/media/usb/uvc/uvcvideo.h
> > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > @@ -12,6 +12,7 @@
> > #include <linux/usb/video.h>
> > #include <linux/uvcvideo.h>
> > #include <linux/videodev2.h>
> > +#include <linux/workqueue.h>
> > #include <media/media-device.h>
> > #include <media/v4l2-device.h>
> > #include <media/v4l2-event.h>
> > @@ -259,6 +260,8 @@ struct uvc_control {
> > initialized:1;
> >
> > u8 *uvc_data;
> > +
> > + struct uvc_fh *handle; /* Used for asynchronous event delivery */
> > };
> >
> > struct uvc_format_desc {
> > @@ -603,6 +606,14 @@ struct uvc_device {
> > u8 *status;
> > struct input_dev *input;
> > char input_phys[64];
> > +
> > + struct uvc_ctrl_work {
> > + struct work_struct work;
> > + struct uvc_video_chain *chain;
> > + struct uvc_control *ctrl;
> > + spinlock_t lock;
> > + void *data;
> > + } async_ctrl;
> > };
> >
> > enum uvc_handle_state {
> > @@ -756,6 +767,8 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> > int uvc_ctrl_init_device(struct uvc_device *dev);
> > void uvc_ctrl_cleanup_device(struct uvc_device *dev);
> > int uvc_ctrl_restore_values(struct uvc_device *dev);
> > +void uvc_ctrl_status_event(struct uvc_video_chain *chain,
> > + struct uvc_control *ctrl, u8 *data, size_t len);
> >
> > int uvc_ctrl_begin(struct uvc_video_chain *chain);
> > int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
> > @@ -773,7 +786,7 @@ static inline int uvc_ctrl_rollback(struct uvc_fh
> > *handle) }
> >
> > int uvc_ctrl_get(struct uvc_video_chain *chain, struct v4l2_ext_control
> > *xctrl); -int uvc_ctrl_set(struct uvc_video_chain *chain, struct
> > v4l2_ext_control *xctrl); +int uvc_ctrl_set(struct uvc_fh *handle, struct
> > v4l2_ext_control *xctrl);
> >
> > int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
> > struct uvc_xu_control_query *xqry);
> > diff --git a/include/uapi/linux/uvcvideo.h b/include/uapi/linux/uvcvideo.h
> > index 020714d2c5bd..f80f05b3c423 100644
> > --- a/include/uapi/linux/uvcvideo.h
> > +++ b/include/uapi/linux/uvcvideo.h
> > @@ -28,6 +28,8 @@
> > #define UVC_CTRL_FLAG_RESTORE (1 << 6)
> > /* Control can be updated by the camera. */
> > #define UVC_CTRL_FLAG_AUTO_UPDATE (1 << 7)
> > +/* Control supports asynchronous reporting */
> > +#define UVC_CTRL_FLAG_ASYNCHRONOUS (1 << 8)
> >
> > #define UVC_CTRL_FLAG_GET_RANGE \
> > (UVC_CTRL_FLAG_GET_CUR | UVC_CTRL_FLAG_GET_MIN | \
>
> --
> Regards,
>
> Laurent Pinchart
>
