[media] media-device: better name Kernelspace/Userspace links
The __media_device_enum_links() copies links definitions from
Kernelspace to userspace. It has to work with 3 structs that
handle with links. Better name them to:
link: Kernelspace internal link representation, of the
type media_link;
klink_desc: struct media_link_desc pointer to the
kernel memory where the data will be filled;
ulink_desc: struct media_link_desc pointer to the
memory where the data will be copied to
userspace.
[media] media-entity: init pads on entity init if was registered before
If an entity is registered with a media device before is initialized
with media_device_register_entity(), the number of pads won't be set
so media_device_register_entity() won't create pad objects and add
it to the media device pads list.
Do this at entity initialization time if the entity was registered
before so the graph is complete and correct regardless of the order
in which the entities are initialized and registered.
[media] media-device: use unsigned ints on some places
The entity->num_pads are defined as u16. So, better to use an
unsigned int, as this prevents additional warnings when W=2
(or W=1 on some architectures).
The "i" counter at __media_device_get_topology() is also a
monotonic counter that should never be below zero. So,
make it unsigned too.
Suggested-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
We should not be creating device nodes at IRQ contexts. So,
the only flags we'll be using will be GFP_KERNEL. Let's
remove the gfp_flags, in order to make the interface simpler.
If we ever need it, it would be easy to revert those changes.
While here, remove an extra blank line.
Suggested-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Indirect links are those whose interface indirectly controls
other functions.
There are two interfaces that have indirect controls at the DVB
side:
- the network interface, which also controls the demux;
- the DVR interface which also controls the demux.
One could argue that the frontend control to the tuner is indirect.
Well, that's debatable. There's no way to create subdev interfaces
for tuner and demod, as those devices are tightly coupled. So, it
was decided that just one interface is the best to control both
entities, and there's no plan (or easy way) to decouple both. So,
the DVB frontend interface should link to both entities.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] media-device: export the entity function via new ioctl
Now that entities have a main function, expose it via
MEDIA_IOC_G_TOPOLOGY ioctl.
Please notice that some entities may have secundary functions.
Such use case will be addressed later, when we add support for the
Media Controller properties.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] v4l2 core: enable all interface links at init
Interface links are normally enabled, meaning that the interfaces are
bound to the entities. So, any ioctl send to the interface are reflected
at the entities managed by the interface.
However, when a device is used, other interfaces for the same hardware
could be decoupled from the entities linked to them, because the
hardware may have some parts busy.
That's for example, what happens when an hybrid TV device is in use.
If it is streaming analog TV or capturing signals from S-Video/Composite
connectors, typically the digital part of the hardware can't be used and
vice-versa.
This is generally due to some internal hardware or firmware limitation,
that it is not easily mapped via data pipelines.
What the Kernel drivers do internally is that they decouple the hardware
from the interface. So, all changes, if allowed, are done only at some
interface cache, but not physically changed at the hardware.
The usage is similar to the usage of the MEDIA_LNK_FL_ENABLED on data
links. So, let's use the same flag to indicate if either the interface
to entity link is bound/enabled or not.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] media-device: supress backlinks at G_TOPOLOGY ioctl
Due to the graph traversal algorithm currently in usage, we
need a copy of all data links. Those backlinks should not be
send to userspace, as otherwise, all links there will be
duplicated.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] dvbdev: returns error if graph object creation fails
Right now, if something gets wrong at dvb_create_media_entity()
or at dvb_create_media_graph(), the device will still be
registered.
Change the logic to properly handle it and free all media graph
objects if something goes wrong at dvb_register_device().
Also, change the logic at dvb_create_media_graph() to return
an error code if something goes wrong. It is up to the
caller to implement the right logic and to call
dvb_unregister_device() to unregister the already-created
objects.
While here, add a missing logic to unregister the created
interfaces.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] media-entity: fix backlink removal on __media_entity_remove_link()
The logic is testing if num_links==0 at the wrong place. Due to
that, a backlink may be kept without removal, causing KASAN
to complain about usage after free during either entity or
link removal.
[media] media: don't try to empty links list in media_entity_cleanup()
The media_entity_cleanup() function only cleans up the entity links list
but this operation is already made in media_device_unregister_entity().
In most cases this should be harmless (besides having duplicated code)
since the links list would be empty so the iteration would not happen
but the links list is initialized in media_device_register_entity() so
if a driver fails to register an entity with a media device and clean up
the entity in the error path, a NULL deference pointer error will happen.
So don't try to empty the links list in media_entity_cleanup() since
is either done already or haven't been initialized yet.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
[media] au0828: postpone call to au0828_unregister_media_device()
The DVB core needs to unregister the media device. So, we
can't call au0828_unregister_media_device() before calling
au0828_dvb_unregister(), otherwise the DVB MC free code
(that will be implemented on the next patch) will fail.
[media] dvbdev: enable all interface links at init
Interface links are normally enabled, meaning that the interfaces are
bound to the entities. So, any ioctl sent to the interface are reflected
at the entities managed by the interface.
However, when a device is in use, other interfaces for the same hardware
could be decoupled from the entities linked to them, because the
hardware may have some parts busy.
That's for example, what happens when an hybrid TV device is in use.
If it is streaming analog TV or capturing signals from S-Video/Composite
connectors, typically the digital part of the hardware can't be used and
vice-versa.
This is generally due to some internal hardware or firmware limitation,
that it is not easily mapped via data pipelines.
What the Kernel drivers do internally is that they decouple the hardware
from the interface. So, all changes, if allowed, are done only at some
interface cache, but not physically changed at the hardware.
The usage is similar to the usage of the MEDIA_LNK_FL_ENABLED on data
links. So, let's use the same flag to indicate if either the interface
to entity link is bound/enabled or not.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] media-entity: protect object creation/removal using spin lock
Some parts of the media controller are using mutexes while
others are using spin locks in order to protect creation
and removal of elements in the graph. That's wrong!
Also, the V4L2 core can remove graph elements on non-interactive
context:
BUG: sleeping function called from invalid context at include/linux/sched.h:2776
Fix it by always using spin locks for graph element addition/removal,
just like entity creation/removal is protected at media-device.c
[media] media_device: add a topology version field
Every time a graph object is added or removed, the version
of the topology changes. That's a requirement for the new
MEDIA_IOC_G_TOPOLOGY, in order to allow userspace to know
that the topology has changed after a previous call to it.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Let's control the topology changes inside the graph_object. So, move the
addition and removal of interfaces/entities from the mdev lists to
media_gobj_init() and media_gobj_remove().
The main reason is that mdev should have lists for all object types, as
the new MC api will require to store objects in separate places.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] dvb: modify core to implement interfaces/entities at MC new gen
The Media Controller New Generation redefines the types for both
interfaces and entities to be used on DVB. Make the needed
changes at the DVB core for all interfaces, entities and
data and interface links to appear in the graph.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] DocBook: update descriptions for the media controller entities
Cleanup the media controller entities description:
- remove MEDIA_ENT_T_DEVNODE and MEDIA_ENT_T_V4L2_SUBDEV entity
types, as they don't mean anything;
- add MEDIA_ENT_T_UNKNOWN with a proper description;
- remove ALSA and FB entity types. Those should not be used, as
the types are deprecated. We'll soon be adidng ALSA, but with
a different entity namespace;
- improve the description of some entities.
This sensor driver is abusing MEDIA_ENT_T_V4L2_SUBDEV, creating
some subdevs with a non-existing type.
As this is a sensor driver, one of the entries is
MEDIA_ENT_T_CAM_SENSOR. The other one will be using
MEDIA_ENT_T_V4L2_SUBDEV_UNKNOWN, because the subdev is not
any of the already existing types.
[media] omap3/omap4/davinci: get rid of MEDIA_ENT_T_V4L2_SUBDEV abuse
On omap3/omap4/davinci drivers, MEDIA_ENT_T_V4L2_SUBDEV macro is
abused in order to "simplify" the pad checks.
Basically, it does a logical or of this macro, in order to check
for a local index and if the entity is either a subdev or not.
As we'll get rid of MEDIA_ENT_T_V4L2_SUBDEV macro, replace it by
2 << 16 where it occurs, and add a note saying that the code
there is actually a hack.
[media] media: use macros to check for V4L2 subdev entities
Instead of relying on media subtype, use the new macros to detect
if an entity is a subdev or an A/V DMA entity.
Please note that most drivers assume that there's just AV_DMA or
V4L2 subdevs. This is not true anymore, as we've added MC support
for DVB, and there are plans to add support for ALSA and FB/DRM
too.
Ok, on the current pipelines supported by those drivers, just V4L
stuff are there, but, assuming that some day a pipeline that also
works with other subsystems will ever added, it is better to add
explicit checks for the AV_DMA stuff.
[media] media: add macros to check if subdev or V4L2 DMA
As we'll be removing entity subtypes from the Kernel, we need
to provide a way for drivers and core to check if a given
entity is represented by a V4L2 subdev or if it is an V4L2
I/O entity (typically with DMA).
Drivers that create entities that don't belong to any defined subdev
category should use MEDIA_ENT_T_V4L2_SUBDEV_UNKNOWN.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] replace all occurrences of MEDIA_ENT_T_DEVNODE_DVB
Now that interfaces and entities are distinct, it makes no sense
of keeping something named as MEDIA_ENT_T_DEVNODE_DVB_foo.
Made via this script:
for i in $(git grep -l MEDIA_ENT_T|grep -v uapi/linux/media.h); do sed s,MEDIA_ENT_T_DEVNODE_DVB_,MEDIA_ENT_T_DVB_, <$i >a && mv a $i; done
for i in $(git grep -l MEDIA_ENT_T|grep -v uapi/linux/media.h); do sed s,MEDIA_ENT_T_DVB_DVR,MEDIA_ENT_T_DVB_TSOUT, <$i >a && mv a $i; done
for i in $(git grep -l MEDIA_ENT_T|grep -v uapi/linux/media.h); do sed s,MEDIA_ENT_T_DVB_FE,MEDIA_ENT_T_DVB_DEMOD, <$i >a && mv a $i; done
for i in $(git grep -l MEDIA_ENT_T|grep -v uapi/linux/media.h); do sed s,MEDIA_ENT_T_DVB_NET,MEDIA_ENT_T_DVB_DEMOD_NET_DECAP, <$i >a && mv a $i; done
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Now that the infrastruct for that is set, add support for
interfaces.
Please notice that we're missing two links:
DVB FE intf -> tuner
DVB demux intf -> dvr
Those should be added latter, after having the entire graph
set. With the current infrastructure, those should be added
at dvb_create_media_graph(), but it would also require some
extra core changes, to allow the function to enumerate the
interfaces.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
The entire logic that represent graph links were developed on a
time where there were no needs to dynamic remove links. So,
although links are created/removed one by one via some
functions, they're stored as an array inside the entity struct.
As the array may grow, there's a logic inside the code that
checks if the amount of space is not enough to store
the needed links. If it isn't the core uses krealloc()
to change the size of the link, with is bad, as it
leaves the memory fragmented.
So, convert links into a list.
Also, currently, both source and sink entities need the link
at the graph traversal logic inside media_entity. So there's
a logic duplicating all links. That makes it to spend
twice the memory needed. This is not a big deal for today's
usage, where the number of links are not big.
Yet, if during the MC workshop discussions, it was said that
IIO graphs could have up to 4,000 entities. So, we may
want to remove the duplication on some future. The problem
is that it would require a separate linked list to store
the backlinks inside the entity, or to use a more complex
algorithm to do graph backlink traversal, with is something
that the current graph traversal inside the core can't cope
with. So, let's postpone a such change if/when it is actually
needed.
It should also be noticed that the media_link structure uses
44 bytes on 32-bit architectures and 84 bytes on 64-bit
architecture. It will thus be allocated out of the 64-bytes and
96-bytes pools respectively. That's a 12.5% memory waste on
64-bit architectures and 31.25% on 32-bit architecture.
A linked list is less efficient than an array in this case, but
this could later be optimized if we can get rid of the reverse
links (with would reduce memory allocation by 50%).
Links are graph objects that represent the links of two already
existing objects in the graph.
While with the current implementation, it is possible to create
the links earlier, It doesn't make any sense to allow linking
two objects when they are not both created.
So, remove the code that would be handling those early-created
links and add a BUG_ON() to ensure that.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] smiapp: create pad links after subdev registration
The smiapp driver creates the pads links before the media entity is
registered with the media device. This doesn't work now that object
IDs are used to create links so the media_device has to be set.
Move entity registration logic before pads links creation.
[media] uvcvideo: create pad links after subdev registration
The uvc driver creates the pads links before the media entity is
registered with the media device. This doesn't work now that obj
IDs are used to create links so the media_device has to be set.
Move entities registration logic before pads links creation.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] v4l: vsp1: separate links creation from entities init
The vsp1 driver initializes the entities and creates the pads links
before the entities are registered with the media device. This doesn't
work now that object IDs are used to create links so the media_device
has to be set.
Split out the pads links creation from the entity initialization so are
made after the entities registration.
[media] v4l: vsp1: create pad links after subdev registration
The vsp1 driver creates the pads links before the media entities are
registered with the media device. This doesn't work now that object
IDs are used to create links so the media_device has to be set.
Move entities registration logic before pads links creation.
[media] staging: omap4iss: separate links creation from entities init
The omap4iss driver initializes the entities and creates the pads links
before the entities are registered with the media device. This does not
work now that object IDs are used to create links so the media_device
has to be set.
Split out the pads links creation from the entity initialization so are
made after the entities registration.
[media] omap3isp: create links after all subdevs have been bound
The omap3isp driver parses the graph endpoints to know how many subdevices
needs to be registered async and register notifiers callbacks for to know
when these are bound and when the async registrations are completed.
Currently the entities pad are linked with the correct ISP input interface
when the subdevs are bound but it happens before entitities are registered
with the media device so that won't work now that the entity links list is
initialized on device registration.
So instead creating the pad links when the subdevice is bound, create them
on the complete callback once all the subdevices have been bound but only
try to create for the ones that have a bus configuration set during bound.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] omap3isp: separate links creation from entities init
The omap3isp driver initializes the entities and creates the pads links
before the entities are registered with the media device. This does not
work now that object IDs are used to create links so the media_device
has to be set.
Split out the pads links creation from the entity initialization so the links
are created after the entities have been registered with the media device.
[media] media: add functions to allow creating interfaces
Interfaces are different than entities: they represent a
Kernel<->userspace interaction, while entities represent a
piece of hardware/firmware/software that executes a function.
Let's distinguish them by creating a separate structure to
store the interfaces.
Later patches should change the existing drivers and logic
to split the current interface embedded inside the entity
structure (device nodes) into a separate object of the graph.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] uapi/media.h: Declare interface types for V4L2 and DVB
Declare the interface types that will be used by the new
G_TOPOLOGY ioctl that will be defined later on.
For now, we need those types, as they'll be used on the
internal structs associated with the new media_interface
graph object defined on the next patch.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Now that the struct media_entity .parent field is unused, it can be
safely removed. Since all the previous users were converted to use
the .mdev field from the embedded struct media_gobj instead.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] media: use entity.graph_obj.mdev instead of .parent
The struct media_entity has a .parent field that stores a pointer
to the parent struct media_device. But recently a media_gobj was
embedded into the entities and since struct media_gojb already has
a pointer to a struct media_device in the .mdev field, the .parent
field becomes redundant and can be removed.
This patch replaces all the usage of .parent by .graph_obj.mdev so
that field will become unused and can be removed on a later patch.
No functional changes.
The transformation was made using the following coccinelle spatch:
[media] media: rename the function that create pad links
With the new API, a link can be either between two PADs or between an interface
and an entity. So, we need to use a better name for the function that create
links between two pads.
So, rename the such function to media_create_pad_link().
No functional changes.
This patch was created via this shell script:
for i in $(find drivers/media -name '*.[ch]' -type f) $(find drivers/staging/media -name '*.[ch]' -type f) $(find include/ -name '*.h' -type f) ; do sed s,media_entity_create_link,media_create_pad_link,g <$i >a && mv a $i; done
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Tested-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
PADs also need unique object IDs that won't conflict with
the entity object IDs.
The pad objects are currently created via media_entity_init()
and, once created, never change.
While this will likely change in the future in order to
support dynamic changes, for now we'll keep PADs as arrays
and initialize the media_gobj embedded structs when
registering the entity.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Tested-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
As entities are graph objects, let's embed media_gobj
on it. That ensures an unique ID for entities that can be
global along the entire media controller.
For now, we'll keep the already existing entity ID. Such
field need to be dropped at some point, but for now, let's
not do this, to avoid needing to review all drivers and
the userspace apps.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Tested-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] media: add a common struct to be embed on media graph objects
Due to the MC API proposed changes, we'll need to have an unique
object ID for all graph objects, and have some shared fields
that will be common on all media graph objects.
Right now, the only common object is the object ID, but other
fields will be added later on.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] omap3isp: get entity ID using media_entity_id()
Accessing media_entity ID should now use media_entity_id() macro to
obtain the entity ID, as a next patch will remove the .id field from
struct media_entity .
So, get rid of it, otherwise the omap3isp driver will fail to build.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] staging: omap4iss: get entity ID using media_entity_id()
Accessing media_entity ID should now use media_entity_id() macro to
obtain the entity ID, as a next patch will remove the .id field from
struct media_entity .
So, get rid of it, otherwise the omap4iss driver will fail to build.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[media] media: get rid of unused "extra_links" param on media_entity_init()
Currently, media_entity_init() creates an array with the links,
allocated at init time. It provides a parameter (extra_links)
that would allocate more links than the current needs, but this
is not used by any driver.
As we want to be able to do dynamic link allocation/removal,
we'll need to change the implementation of the links. So,
before doing that, let's first remove that extra unused
parameter, in order to cleanup the interface first.
Shuah Khan [Fri, 5 Jun 2015 20:11:54 +0000 (17:11 -0300)]
[media] media: define Media Controller API when CONFIG_MEDIA_CONTROLLER enabled
Change to define Media Controller API when CONFIG_MEDIA_CONTROLLER
is enabled. Define stubs for CONFIG_MEDIA_CONTROLLER disabled case.
This will help avoid drivers needing to enclose Media Controller
code within ifdef CONFIG_MEDIA_CONTROLLER block.
Shuah Khan [Wed, 3 Jun 2015 15:12:53 +0000 (12:12 -0300)]
[media] media: new media controller API for device resource support
Add new media controller API to allocate media device as a
device resource. When a media device is created on the main
struct device which is the parent device for the interface
device, it will be available to all drivers associated with
that interface. For example, if a usb media device driver
creates the media device on the main struct device which is
common for all the drivers that control the media device,
including the non-media ALSA driver, media controller API
can be used to share access to the resources on the media
device. This new interface provides the above described
feature. A second interface that finds and returns the media
device is added to allow drivers to find the media device
created by any of the drivers associated with the device.
Chen-Yu Tsai [Tue, 22 Dec 2015 04:27:35 +0000 (02:27 -0200)]
[media] rc: sunxi-cir: Initialize the spinlock properly
The driver allocates the spinlock but fails to initialize it correctly.
The kernel reports a BUG indicating bad spinlock magic when spinlock
debugging is enabled.
Call spin_lock_init() on it to initialize it correctly.
Antti Palosaari [Mon, 5 Oct 2015 23:46:37 +0000 (20:46 -0300)]
[media] rtl28xxu: return demod reg page from driver cache
Return current active rtl2830/rtl2832 register page from the driver
cache in order to reduce I2C I/O. Register page is already cached
due to I2C write needs.
Signed-off-by: Antti Palosaari <crope@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Philipp Zabel [Wed, 2 Dec 2015 16:58:53 +0000 (14:58 -0200)]
[media] coda: don't start streaming without queued buffers
We could support start streaming with an empty output queue for the
BIT decoders due to the bitstream buffer which could still contain
data at this point, but there is really no reason for userspace to
expect this to work. Simplify the code by disallowing it.