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linux/drivers/media/v4l2-core/v4l2-mc.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Media Controller ancillary functions
*
* Copyright (c) 2016 Mauro Carvalho Chehab <mchehab@kernel.org>
* Copyright (C) 2016 Shuah Khan <shuahkh@osg.samsung.com>
* Copyright (C) 2006-2010 Nokia Corporation
* Copyright (c) 2016 Intel Corporation.
*/
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/usb.h>
#include <media/media-device.h>
#include <media/media-entity.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-mc.h>
#include <media/v4l2-subdev.h>
#include <media/videobuf2-core.h>
int v4l2_mc_create_media_graph(struct media_device *mdev)
{
struct media_entity *entity;
struct media_entity *if_vid = NULL, *if_aud = NULL;
struct media_entity *tuner = NULL, *decoder = NULL;
struct media_entity *io_v4l = NULL, *io_vbi = NULL, *io_swradio = NULL;
bool is_webcam = false;
u32 flags;
int ret, pad_sink, pad_source;
if (!mdev)
return 0;
media_device_for_each_entity(entity, mdev) {
switch (entity->function) {
case MEDIA_ENT_F_IF_VID_DECODER:
if_vid = entity;
break;
case MEDIA_ENT_F_IF_AUD_DECODER:
if_aud = entity;
break;
case MEDIA_ENT_F_TUNER:
tuner = entity;
break;
case MEDIA_ENT_F_ATV_DECODER:
decoder = entity;
break;
case MEDIA_ENT_F_IO_V4L:
io_v4l = entity;
break;
case MEDIA_ENT_F_IO_VBI:
io_vbi = entity;
break;
case MEDIA_ENT_F_IO_SWRADIO:
io_swradio = entity;
break;
case MEDIA_ENT_F_CAM_SENSOR:
is_webcam = true;
break;
}
}
/* It should have at least one I/O entity */
if (!io_v4l && !io_vbi && !io_swradio) {
dev_warn(mdev->dev, "Didn't find any I/O entity\n");
return -EINVAL;
}
/*
* Here, webcams are modelled on a very simple way: the sensor is
* connected directly to the I/O entity. All dirty details, like
* scaler and crop HW are hidden. While such mapping is not enough
* for mc-centric hardware, it is enough for v4l2 interface centric
* PC-consumer's hardware.
*/
if (is_webcam) {
if (!io_v4l) {
dev_warn(mdev->dev, "Didn't find a MEDIA_ENT_F_IO_V4L\n");
return -EINVAL;
}
media_device_for_each_entity(entity, mdev) {
if (entity->function != MEDIA_ENT_F_CAM_SENSOR)
continue;
ret = media_create_pad_link(entity, 0,
io_v4l, 0,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "Failed to create a sensor link\n");
return ret;
}
}
if (!decoder)
return 0;
}
/* The device isn't a webcam. So, it should have a decoder */
if (!decoder) {
dev_warn(mdev->dev, "Decoder not found\n");
return -EINVAL;
}
/* Link the tuner and IF video output pads */
if (tuner) {
if (if_vid) {
pad_source = media_get_pad_index(tuner,
MEDIA_PAD_FL_SOURCE,
PAD_SIGNAL_ANALOG);
pad_sink = media_get_pad_index(if_vid,
MEDIA_PAD_FL_SINK,
PAD_SIGNAL_ANALOG);
if (pad_source < 0 || pad_sink < 0) {
dev_warn(mdev->dev, "Couldn't get tuner and/or PLL pad(s): (%d, %d)\n",
pad_source, pad_sink);
return -EINVAL;
}
ret = media_create_pad_link(tuner, pad_source,
if_vid, pad_sink,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "Couldn't create tuner->PLL link)\n");
return ret;
}
pad_source = media_get_pad_index(if_vid,
MEDIA_PAD_FL_SOURCE,
PAD_SIGNAL_ANALOG);
pad_sink = media_get_pad_index(decoder,
MEDIA_PAD_FL_SINK,
PAD_SIGNAL_ANALOG);
if (pad_source < 0 || pad_sink < 0) {
dev_warn(mdev->dev, "get decoder and/or PLL pad(s): (%d, %d)\n",
pad_source, pad_sink);
return -EINVAL;
}
ret = media_create_pad_link(if_vid, pad_source,
decoder, pad_sink,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link PLL to decoder\n");
return ret;
}
} else {
pad_source = media_get_pad_index(tuner,
MEDIA_PAD_FL_SOURCE,
PAD_SIGNAL_ANALOG);
pad_sink = media_get_pad_index(decoder,
MEDIA_PAD_FL_SINK,
PAD_SIGNAL_ANALOG);
if (pad_source < 0 || pad_sink < 0) {
dev_warn(mdev->dev, "couldn't get tuner and/or decoder pad(s): (%d, %d)\n",
pad_source, pad_sink);
return -EINVAL;
}
ret = media_create_pad_link(tuner, pad_source,
decoder, pad_sink,
MEDIA_LNK_FL_ENABLED);
if (ret)
return ret;
}
if (if_aud) {
pad_source = media_get_pad_index(tuner,
MEDIA_PAD_FL_SOURCE,
PAD_SIGNAL_AUDIO);
pad_sink = media_get_pad_index(if_aud,
MEDIA_PAD_FL_SINK,
PAD_SIGNAL_AUDIO);
if (pad_source < 0 || pad_sink < 0) {
dev_warn(mdev->dev, "couldn't get tuner and/or decoder pad(s) for audio: (%d, %d)\n",
pad_source, pad_sink);
return -EINVAL;
}
ret = media_create_pad_link(tuner, pad_source,
if_aud, pad_sink,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link tuner->audio PLL\n");
return ret;
}
} else {
if_aud = tuner;
}
}
/* Create demod to V4L, VBI and SDR radio links */
if (io_v4l) {
pad_source = media_get_pad_index(decoder, MEDIA_PAD_FL_SOURCE,
PAD_SIGNAL_DV);
if (pad_source < 0) {
dev_warn(mdev->dev, "couldn't get decoder output pad for V4L I/O\n");
return -EINVAL;
}
ret = media_create_pad_link(decoder, pad_source,
io_v4l, 0,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link decoder output to V4L I/O\n");
return ret;
}
}
if (io_swradio) {
pad_source = media_get_pad_index(decoder, MEDIA_PAD_FL_SOURCE,
PAD_SIGNAL_DV);
if (pad_source < 0) {
dev_warn(mdev->dev, "couldn't get decoder output pad for SDR\n");
return -EINVAL;
}
ret = media_create_pad_link(decoder, pad_source,
io_swradio, 0,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link decoder output to SDR\n");
return ret;
}
}
if (io_vbi) {
pad_source = media_get_pad_index(decoder, MEDIA_PAD_FL_SOURCE,
PAD_SIGNAL_DV);
if (pad_source < 0) {
dev_warn(mdev->dev, "couldn't get decoder output pad for VBI\n");
return -EINVAL;
}
ret = media_create_pad_link(decoder, pad_source,
io_vbi, 0,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link decoder output to VBI\n");
return ret;
}
}
/* Create links for the media connectors */
flags = MEDIA_LNK_FL_ENABLED;
media_device_for_each_entity(entity, mdev) {
switch (entity->function) {
case MEDIA_ENT_F_CONN_RF:
if (!tuner)
continue;
pad_sink = media_get_pad_index(tuner, MEDIA_PAD_FL_SINK,
PAD_SIGNAL_ANALOG);
if (pad_sink < 0) {
dev_warn(mdev->dev, "couldn't get tuner analog pad sink\n");
return -EINVAL;
}
ret = media_create_pad_link(entity, 0, tuner,
pad_sink,
flags);
break;
case MEDIA_ENT_F_CONN_SVIDEO:
case MEDIA_ENT_F_CONN_COMPOSITE:
pad_sink = media_get_pad_index(decoder,
MEDIA_PAD_FL_SINK,
PAD_SIGNAL_ANALOG);
if (pad_sink < 0) {
dev_warn(mdev->dev, "couldn't get decoder analog pad sink\n");
return -EINVAL;
}
ret = media_create_pad_link(entity, 0, decoder,
pad_sink,
flags);
break;
default:
continue;
}
if (ret)
return ret;
flags = 0;
}
return 0;
}
EXPORT_SYMBOL_GPL(v4l2_mc_create_media_graph);
int v4l_enable_media_source(struct video_device *vdev)
{
struct media_device *mdev = vdev->entity.graph_obj.mdev;
[media] media: Protect enable_source and disable_source handler code paths Drivers might try to access and run enable_source and disable_source handlers when the driver that implements these handlers is clearing the handlers during its unregister. Fix the following race condition: process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (doesn't hold graph_mutex) mdev->enable_source = NULL; if (mdev && mdev->enable_source) mdev->disable_source = NULL; mdev->enable_source() (enable_source holds graph_mutex) As shown above enable_source check is done without holding the graph_mutex. If unbind happens to be in progress, au0828 could clear enable_source and disable_source handlers leading to null pointer de-reference. Fix it by protecting enable_source and disable_source set and clear and protecting enable_source and disable_source handler access and the call itself. process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (hold graph_mutex while clearing) mdev->enable_source = NULL; if (mdev) mdev->disable_source = NULL; (hold graph_mutex to check and call enable_source) if (mdev->enable_source) mdev->enable_source() If graph_mutex is held to just heck for handler being null and needs to be released before calling the handler, there will be another window for the handlers to be cleared. Hence, enable_source and disable_source handlers no longer hold the graph_mutex and expect callers to hold it to avoid forcing them release the graph_mutex before calling the handlers. Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2016-11-29 16:59:54 -07:00
int ret = 0, err;
[media] media: Protect enable_source and disable_source handler code paths Drivers might try to access and run enable_source and disable_source handlers when the driver that implements these handlers is clearing the handlers during its unregister. Fix the following race condition: process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (doesn't hold graph_mutex) mdev->enable_source = NULL; if (mdev && mdev->enable_source) mdev->disable_source = NULL; mdev->enable_source() (enable_source holds graph_mutex) As shown above enable_source check is done without holding the graph_mutex. If unbind happens to be in progress, au0828 could clear enable_source and disable_source handlers leading to null pointer de-reference. Fix it by protecting enable_source and disable_source set and clear and protecting enable_source and disable_source handler access and the call itself. process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (hold graph_mutex while clearing) mdev->enable_source = NULL; if (mdev) mdev->disable_source = NULL; (hold graph_mutex to check and call enable_source) if (mdev->enable_source) mdev->enable_source() If graph_mutex is held to just heck for handler being null and needs to be released before calling the handler, there will be another window for the handlers to be cleared. Hence, enable_source and disable_source handlers no longer hold the graph_mutex and expect callers to hold it to avoid forcing them release the graph_mutex before calling the handlers. Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2016-11-29 16:59:54 -07:00
if (!mdev)
return 0;
[media] media: Protect enable_source and disable_source handler code paths Drivers might try to access and run enable_source and disable_source handlers when the driver that implements these handlers is clearing the handlers during its unregister. Fix the following race condition: process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (doesn't hold graph_mutex) mdev->enable_source = NULL; if (mdev && mdev->enable_source) mdev->disable_source = NULL; mdev->enable_source() (enable_source holds graph_mutex) As shown above enable_source check is done without holding the graph_mutex. If unbind happens to be in progress, au0828 could clear enable_source and disable_source handlers leading to null pointer de-reference. Fix it by protecting enable_source and disable_source set and clear and protecting enable_source and disable_source handler access and the call itself. process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (hold graph_mutex while clearing) mdev->enable_source = NULL; if (mdev) mdev->disable_source = NULL; (hold graph_mutex to check and call enable_source) if (mdev->enable_source) mdev->enable_source() If graph_mutex is held to just heck for handler being null and needs to be released before calling the handler, there will be another window for the handlers to be cleared. Hence, enable_source and disable_source handlers no longer hold the graph_mutex and expect callers to hold it to avoid forcing them release the graph_mutex before calling the handlers. Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2016-11-29 16:59:54 -07:00
mutex_lock(&mdev->graph_mutex);
if (!mdev->enable_source)
goto end;
err = mdev->enable_source(&vdev->entity, &vdev->pipe);
if (err)
ret = -EBUSY;
end:
mutex_unlock(&mdev->graph_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(v4l_enable_media_source);
void v4l_disable_media_source(struct video_device *vdev)
{
struct media_device *mdev = vdev->entity.graph_obj.mdev;
[media] media: Protect enable_source and disable_source handler code paths Drivers might try to access and run enable_source and disable_source handlers when the driver that implements these handlers is clearing the handlers during its unregister. Fix the following race condition: process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (doesn't hold graph_mutex) mdev->enable_source = NULL; if (mdev && mdev->enable_source) mdev->disable_source = NULL; mdev->enable_source() (enable_source holds graph_mutex) As shown above enable_source check is done without holding the graph_mutex. If unbind happens to be in progress, au0828 could clear enable_source and disable_source handlers leading to null pointer de-reference. Fix it by protecting enable_source and disable_source set and clear and protecting enable_source and disable_source handler access and the call itself. process 1 process 2 request video streaming unbind au0828 v4l2 checks if tuner is free ... ... au0828_unregister_media_device() ... ... (hold graph_mutex while clearing) mdev->enable_source = NULL; if (mdev) mdev->disable_source = NULL; (hold graph_mutex to check and call enable_source) if (mdev->enable_source) mdev->enable_source() If graph_mutex is held to just heck for handler being null and needs to be released before calling the handler, there will be another window for the handlers to be cleared. Hence, enable_source and disable_source handlers no longer hold the graph_mutex and expect callers to hold it to avoid forcing them release the graph_mutex before calling the handlers. Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2016-11-29 16:59:54 -07:00
if (mdev) {
mutex_lock(&mdev->graph_mutex);
if (mdev->disable_source)
mdev->disable_source(&vdev->entity);
mutex_unlock(&mdev->graph_mutex);
}
}
EXPORT_SYMBOL_GPL(v4l_disable_media_source);
int v4l_vb2q_enable_media_source(struct vb2_queue *q)
{
struct v4l2_fh *fh = q->owner;
if (fh && fh->vdev)
return v4l_enable_media_source(fh->vdev);
return 0;
}
EXPORT_SYMBOL_GPL(v4l_vb2q_enable_media_source);
int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
struct media_pad *sink, u32 flags)
{
struct fwnode_handle *endpoint;
if (!(sink->flags & MEDIA_PAD_FL_SINK))
return -EINVAL;
fwnode_graph_for_each_endpoint(dev_fwnode(src_sd->dev), endpoint) {
struct fwnode_handle *remote_ep;
int src_idx, sink_idx, ret;
struct media_pad *src;
src_idx = media_entity_get_fwnode_pad(&src_sd->entity,
endpoint,
MEDIA_PAD_FL_SOURCE);
if (src_idx < 0) {
dev_dbg(src_sd->dev, "no source pad found for %pfw\n",
endpoint);
continue;
}
remote_ep = fwnode_graph_get_remote_endpoint(endpoint);
if (!remote_ep) {
dev_dbg(src_sd->dev, "no remote ep found for %pfw\n",
endpoint);
continue;
}
/*
* ask the sink to verify it owns the remote endpoint,
* and translate to a sink pad.
*/
sink_idx = media_entity_get_fwnode_pad(sink->entity,
remote_ep,
MEDIA_PAD_FL_SINK);
fwnode_handle_put(remote_ep);
if (sink_idx < 0 || sink_idx != sink->index) {
dev_dbg(src_sd->dev,
"sink pad index mismatch or error (is %d, expected %u)\n",
sink_idx, sink->index);
continue;
}
/*
* the source endpoint corresponds to one of its source pads,
* the source endpoint connects to an endpoint at the sink
* entity, and the sink endpoint corresponds to the sink
* pad requested, so we have found an endpoint connection
* that works, create the media link for it.
*/
src = &src_sd->entity.pads[src_idx];
/* skip if link already exists */
if (media_entity_find_link(src, sink)) {
dev_dbg(src_sd->dev,
"link %s:%d -> %s:%d already exists\n",
src_sd->entity.name, src_idx,
sink->entity->name, sink_idx);
continue;
}
dev_dbg(src_sd->dev, "creating link %s:%d -> %s:%d\n",
src_sd->entity.name, src_idx,
sink->entity->name, sink_idx);
ret = media_create_pad_link(&src_sd->entity, src_idx,
sink->entity, sink_idx, flags);
if (ret) {
dev_err(src_sd->dev,
"link %s:%d -> %s:%d failed with %d\n",
src_sd->entity.name, src_idx,
sink->entity->name, sink_idx, ret);
fwnode_handle_put(endpoint);
return ret;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(v4l2_create_fwnode_links_to_pad);
int v4l2_create_fwnode_links(struct v4l2_subdev *src_sd,
struct v4l2_subdev *sink_sd)
{
unsigned int i;
for (i = 0; i < sink_sd->entity.num_pads; i++) {
struct media_pad *pad = &sink_sd->entity.pads[i];
int ret;
if (!(pad->flags & MEDIA_PAD_FL_SINK))
continue;
ret = v4l2_create_fwnode_links_to_pad(src_sd, pad, 0);
if (ret)
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(v4l2_create_fwnode_links);
/* -----------------------------------------------------------------------------
* Pipeline power management
*
* Entities must be powered up when part of a pipeline that contains at least
* one open video device node.
*
* To achieve this use the entity use_count field to track the number of users.
* For entities corresponding to video device nodes the use_count field stores
* the users count of the node. For entities corresponding to subdevs the
* use_count field stores the total number of users of all video device nodes
* in the pipeline.
*
* The v4l2_pipeline_pm_{get, put}() functions must be called in the open() and
* close() handlers of video device nodes. It increments or decrements the use
* count of all subdev entities in the pipeline.
*
* To react to link management on powered pipelines, the link setup notification
* callback updates the use count of all entities in the source and sink sides
* of the link.
*/
/*
* pipeline_pm_use_count - Count the number of users of a pipeline
* @entity: The entity
*
* Return the total number of users of all video device nodes in the pipeline.
*/
static int pipeline_pm_use_count(struct media_entity *entity,
struct media_graph *graph)
{
int use = 0;
media_graph_walk_start(graph, entity);
while ((entity = media_graph_walk_next(graph))) {
if (is_media_entity_v4l2_video_device(entity))
use += entity->use_count;
}
return use;
}
/*
* pipeline_pm_power_one - Apply power change to an entity
* @entity: The entity
* @change: Use count change
*
* Change the entity use count by @change. If the entity is a subdev update its
* power state by calling the core::s_power operation when the use count goes
* from 0 to != 0 or from != 0 to 0.
*
* Return 0 on success or a negative error code on failure.
*/
static int pipeline_pm_power_one(struct media_entity *entity, int change)
{
struct v4l2_subdev *subdev;
int ret;
subdev = is_media_entity_v4l2_subdev(entity)
? media_entity_to_v4l2_subdev(entity) : NULL;
if (entity->use_count == 0 && change > 0 && subdev != NULL) {
ret = v4l2_subdev_call(subdev, core, s_power, 1);
if (ret < 0 && ret != -ENOIOCTLCMD)
return ret;
}
entity->use_count += change;
WARN_ON(entity->use_count < 0);
if (entity->use_count == 0 && change < 0 && subdev != NULL)
v4l2_subdev_call(subdev, core, s_power, 0);
return 0;
}
/*
* pipeline_pm_power - Apply power change to all entities in a pipeline
* @entity: The entity
* @change: Use count change
*
* Walk the pipeline to update the use count and the power state of all non-node
* entities.
*
* Return 0 on success or a negative error code on failure.
*/
static int pipeline_pm_power(struct media_entity *entity, int change,
struct media_graph *graph)
{
struct media_entity *first = entity;
int ret = 0;
if (!change)
return 0;
media_graph_walk_start(graph, entity);
while (!ret && (entity = media_graph_walk_next(graph)))
if (is_media_entity_v4l2_subdev(entity))
ret = pipeline_pm_power_one(entity, change);
if (!ret)
return ret;
media_graph_walk_start(graph, first);
while ((first = media_graph_walk_next(graph))
&& first != entity)
if (is_media_entity_v4l2_subdev(first))
pipeline_pm_power_one(first, -change);
return ret;
}
static int v4l2_pipeline_pm_use(struct media_entity *entity, unsigned int use)
{
struct media_device *mdev = entity->graph_obj.mdev;
int change = use ? 1 : -1;
int ret;
mutex_lock(&mdev->graph_mutex);
/* Apply use count to node. */
entity->use_count += change;
WARN_ON(entity->use_count < 0);
/* Apply power change to connected non-nodes. */
ret = pipeline_pm_power(entity, change, &mdev->pm_count_walk);
if (ret < 0)
entity->use_count -= change;
mutex_unlock(&mdev->graph_mutex);
return ret;
}
int v4l2_pipeline_pm_get(struct media_entity *entity)
{
return v4l2_pipeline_pm_use(entity, 1);
}
EXPORT_SYMBOL_GPL(v4l2_pipeline_pm_get);
void v4l2_pipeline_pm_put(struct media_entity *entity)
{
/* Powering off entities shouldn't fail. */
WARN_ON(v4l2_pipeline_pm_use(entity, 0));
}
EXPORT_SYMBOL_GPL(v4l2_pipeline_pm_put);
int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
unsigned int notification)
{
struct media_graph *graph = &link->graph_obj.mdev->pm_count_walk;
struct media_entity *source = link->source->entity;
struct media_entity *sink = link->sink->entity;
int source_use;
int sink_use;
int ret = 0;
source_use = pipeline_pm_use_count(source, graph);
sink_use = pipeline_pm_use_count(sink, graph);
if (notification == MEDIA_DEV_NOTIFY_POST_LINK_CH &&
!(flags & MEDIA_LNK_FL_ENABLED)) {
/* Powering off entities is assumed to never fail. */
pipeline_pm_power(source, -sink_use, graph);
pipeline_pm_power(sink, -source_use, graph);
return 0;
}
if (notification == MEDIA_DEV_NOTIFY_PRE_LINK_CH &&
(flags & MEDIA_LNK_FL_ENABLED)) {
ret = pipeline_pm_power(source, sink_use, graph);
if (ret < 0)
return ret;
ret = pipeline_pm_power(sink, source_use, graph);
if (ret < 0)
pipeline_pm_power(source, -sink_use, graph);
}
return ret;
}
EXPORT_SYMBOL_GPL(v4l2_pipeline_link_notify);