The V4L2_CID_3A_LOCK bitmask control allows applications to pause
or resume the automatic exposure, focus and wite balance adjustments.
It can be used, for example, to lock the 3A adjustments right before
a still image is captured, for pre-focus, etc.
The applications can control each of the algorithms independently,
through a corresponding control bit, if driver allows that.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add control for the scene mode feature available in image sensor
with more advanced ISP firmware. The V4L2_CID_SCENE_MODE menu
control allows to select a set of parameters or a specific image
processing and capture control algorithm optimized for common
image capture conditions.
Signed-off-by: HeungJun Kim <riverful.kim@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The V4L2_CID_EXPOSURE_METERING control allows to determine
a method used by the camera for measuring the amount of light
available for automatic exposure.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add ISO sensitivity and ISO auto/manual controls. The sensitivity
values are related to level of amplification of the analog signal
between image sensor and ADC. These controls allow to support sensors
exposing an interface to accept the ISO values directly.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add V4L2_CID_IMAGE_STABILIZATION control for the camera image
stabilization feature. This control can be used to enable/disable
image stabilization. It might get converted to a menu control
in future if more options are needed.
Signed-off-by: HeungJun Kim <riverful.kim@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add V4L2_CID_WIDE_DYNAMIC_RANGE camera class control for the
camera wide dynamic range (WDR, HDR) feature. This control
can be used to enable/disable wide dynamic range. It might
get converted to a menu control in future if more options
are needed.
Signed-off-by: HeungJun Kim <riverful.kim@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This patch adds V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE control which is
an extended version of the V4L2_CID_AUTO_WHITE_BALANCE control,
including white balance presets. The following presets are defined:
- V4L2_WHITE_BALANCE_INCANDESCENT,
- V4L2_WHITE_BALANCE_FLUORESCENT,
- V4L2_WHITE_BALANCE_FLUORESCENT_H,
- V4L2_WHITE_BALANCE_HORIZON,
- V4L2_WHITE_BALANCE_DAYLIGHT,
- V4L2_WHITE_BALANCE_FLASH,
- V4L2_WHITE_BALANCE_CLOUDY,
- V4L2_WHITE_BALANCE_SHADE.
Signed-off-by: HeungJun Kim <riverful.kim@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The camera may in some conditions incorrectly determine the exposure,
and a manual automatic exposure correction may be needed. This patch
adds V4L2_CID_AUTO_EXPOSURE_BIAS control which allows to add some
offset in the automatic exposure control loop, to compensate for
frame under- or over-exposure.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This patch adds v4l2_ctrl_new_int_menu() helper function which can be used
in drivers for creating standard integer menu control with driver-specific
menu item list. It is similar to v4l2_ctrl_new_std_menu(), except it doesn't
have a mask parameter and an additional qmenu parameter allows passing
an array of signed 64-bit integers as the menu item list.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Tested-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This patch adds definition of additional color effects:
- V4L2_COLORFX_AQUA,
- V4L2_COLORFX_ART_FREEZE,
- V4L2_COLORFX_SILHOUETTE,
- V4L2_COLORFX_SOLARIZATION,
- V4L2_COLORFX_ANTIQUE,
- V4L2_COLORFX_SET_CBCR.
The new V4L2_COLORFX_CBCR control is added to allow setting
the fixed Cb, Cr values that replace chroma Cb/Cr coefficients
in case of V4L2_COLORFX_SET_CBCR effect.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Allow choosing the lock used by the control handler. This may be handy
sometimes when a driver providing multiple subdevs does not want to use
several locks to serialise its functions.
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add control class for image processing controls. The control class deals
with controls processing image, for example digital gain or noise filtering,
which can be present in any part of the pipeline.
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add image source control class. This control class is intended to contain
low level controls which deal with control of the image capture process ---
the A/D converter in image sensors, for example.
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Just like with ctrl events, drivers may want to get called back on
listener add / remove for other event types too. Rather then special
casing all of this in subscribe / unsubscribe event it is better to
use ops for this.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Those fields are meaningless for such control types, and the control framework
should zero them. Otherwise v4l2-compliance will complain about non-zero
min/max/step/def fields.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
A large cs->count from userspace may overflow the allocation size,
leading to memory corruption. try_set_ext_ctrls() can be reached
from subdev_do_ioctl() or __video_do_ioctl().
Use kmalloc_array() to avoid the overflow.
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
A large cs->count from userspace may overflow the allocation size,
leading to memory corruption. v4l2_g_ext_ctrls() can be reached
from subdev_do_ioctl() or __video_do_ioctl().
Use kmalloc_array() to avoid the overflow.
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Create a new control type called V4L2_CTRL_TYPE_INTEGER_MENU. Integer menu
controls are just like menu controls but the menu items are 64-bit integers
rather than strings.
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Currently v4l2_ctrl_add_handler adds only the controls that are owned
by the handler. This is wrong. Instead all controls, whether owned or
not, should be added.
This is also implied by the v4l2-controls.txt documentation and it is
clearly the right thing to do. The only reason this was never noticed
before is because we never did this. Only recent changes in ivtv made
this error visible because there a third handler layer was added (handler
A inherits from handler B which inherits from C, D and E). Without this
change handler A only sees the controls owned by handler B and the controls
from C, D and E are missing.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The V4L2_CID_JPEG_CLASS control class is intended to expose various
adjustable parameters of JPEG encoders and decoders. Following controls
are defined:
- V4L2_CID_JPEG_CHROMA_SUBSAMPLING,
- V4L2_CID_JPEG_RESTART_INTERVAL,
- V4L2_CID_JPEG_COMPRESSION_QUALITY,
- V4L2_CID_JPEG_ACTIVE_MARKER.
This covers only a part of relevant standard specifications. More
controls should be added in future if required.
The purpose of V4L2_CID_JPEG_CLASS class is also to replace some
functionality covered by VIDIOC_S/G_JPEGCOMP ioctls, i.e. the JPEG
markers presence and compression quality control. The applications
and drivers should switch from the ioctl to control based API, as
described in the subsequent patches for the Media API DocBook.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Many drivers just support control events, and most radio drivers just need
to poll for control events. Add some functions to simplify those jobs.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
For drivers that properly use the v4l2 framework (i.e. set v4l2_dev in the
video_device struct), the start and end messages of VIDIOC_LOG_STATUS are
now generated automatically. People tended to forget these, but the v4l2-ctl
tool scans for these messages, and it also makes it easier to read the status
output in the kernel log.
The cx18, ivtv and bttv drivers were changed since they no longer need to
log these start/end messages.
In saa7164 two empty log_status functions were removed.
Also added a helper function to v4l2-ctrl.c that can be used as the
vidioc_log_status callback if all you need to do is to log the current control
values. This is now used by pwc and vivi.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Steven Toth <stoth@kernellabs.com>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
As discussed during the 2011 V4L-DVB workshop we want to create a proper V4L2
decoder API that replaces the DVBv5 API that has been used until now.
This adds the four controls necessary to be able to switch ivtv over to this
new API.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Several control names used inconsistent capitalization or were inconsistent
in other ways. I also corrected a spelling mistake and fixed four strings
that were too long (>31 characters). Harmless, but the string is cut off when
it is returned with QUERYCTRL.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The advantage of kcalloc is, that will prevent integer overflows which could
result from the multiplication of number of elements and size and it is also
a bit nicer to read.
The semantic patch that makes this change is available
in https://lkml.org/lkml/2011/11/25/107
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The V4L2_CID_ALPHA_COMPONENT control is intended for the video capture
or memory-to-memory devices that are capable of setting up the per-pixel
alpha component to some arbitrary value. It allows to set the alpha
component for all pixels to an arbitrary value.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
* 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
[media] v4l2-ctrl: Send change events to all fh for auto cluster slave controls
[media] v4l2-event: Don't set sev->fh to NULL on unsubscribe
[media] v4l2-event: Remove pending events from fh event queue when unsubscribing
[media] v4l2-event: Deny subscribing with a type of V4L2_EVENT_ALL
[media] MAINTAINERS: add a maintainer for s5p-mfc driver
[media] v4l: s5p-mfc: fix reported capabilities
[media] media: vb2: reset queued list on REQBUFS(0) call
[media] media: vb2: set buffer length correctly for all buffer types
[media] media: vb2: add a check for uninitialized buffer
[media] mxl111sf: fix build warning
[media] mxl111sf: remove pointless if condition in mxl111sf_config_spi
[media] mxl111sf: check for errors after mxl111sf_write_reg in mxl111sf_idac_config
[media] mxl111sf: fix return value of mxl111sf_idac_config
[media] uvcvideo: GET_RES should only be checked for BITMAP type menu controls
Otherwise the fh changing the master control won't get the inactive state
change event for the slave controls.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Setting sev->fh to NULL causes problems for the del op added in the next
patch of this series, since this op needs a way to get to its own data
structures, and typically this will be done by using container_of on an
embedded v4l2_fh struct.
The reason the original code is setting sev->fh to NULL is to signal
to users of the event framework that the unsubscription has happened,
but since their is no shared lock between the event framework and users
of it, this is inherently racy, and it also turns out to be unnecessary
as long as both the event framework and the user of the framework do their
own locking properly and the user guarantees that it holds no references
to the subcribed_event structure after its del operation has been called.
This is best explained by looking at the only code currently checking for
sev->fh being set to NULL on unsubscribe, which is the v4l2-ctrls.c send_event
function. Here is the relevant code from v4l2-ctrls: send_event():
if (sev->fh && (sev->fh != fh ||
(sev->flags & V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK)))
v4l2_event_queue_fh(sev->fh, &ev);
Now lets say that v4l2_event_unsubscribe and v4l2-ctrls: send_event() race
on the same sev, then the following could happens:
1) send_event checks sev->fh, finds it is not NULL
<thread switch>
2) v4l2_event_unsubscribe sets sev->fh NULL
3) v4l2_event_unsubscribe calls v4l2_ctrls del_event function, this blocks
as the thread calling send_event holds the ctrl_lock
<thread switch>
4) send_event calls v4l2_event_queue_fh(sev->fh, &ev) which not is equivalent
to calling: v4l2_event_queue_fh(NULL, &ev)
5) oops, NULL pointer deref.
Now again without setting sev->fh to NULL in v4l2_event_unsubscribe and
without the (now senseless since always true) sev->fh != NULL check in
1) send_event is about to call v4l2_event_queue_fh(sev->fh, &ev)
<thread switch>
2) v4l2_event_unsubscribe removes sev->list from the fh->subscribed list
<thread switch>
3) send_event calls v4l2_event_queue_fh(sev->fh, &ev)
4) v4l2_event_queue_fh blocks on the fh_lock spinlock
<thread switch>
5) v4l2_event_unsubscribe unlocks the fh_lock spinlock
6) v4l2_event_unsubscribe calls v4l2_ctrls del_event function, this blocks
as the thread calling send_event holds the ctrl_lock
<thread switch>
8) v4l2_event_queue_fh takes the fh_lock
7) v4l2_event_queue_fh calls v4l2_event_subscribed, does not find it since
sev->list has been removed from fh->subscribed already -> does nothing
9) v4l2_event_queue_fh releases the fh_lock
10) the caller of send_event releases the ctrl lock (mutex)
<thread switch>
11) v4l2_ctrls del_event takes the ctrl lock
12) v4l2_ctrls del_event removes sev->node from the ev_subs list
13) v4l2_ctrls del_event releases the ctrl lock
14) v4l2_event_unsubscribe frees the sev, to which no references are being
held anymore
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
Revert "tracing: Include module.h in define_trace.h"
irq: don't put module.h into irq.h for tracking irqgen modules.
bluetooth: macroize two small inlines to avoid module.h
ip_vs.h: fix implicit use of module_get/module_put from module.h
nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
include: replace linux/module.h with "struct module" wherever possible
include: convert various register fcns to macros to avoid include chaining
crypto.h: remove unused crypto_tfm_alg_modname() inline
uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
pm_runtime.h: explicitly requires notifier.h
linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
miscdevice.h: fix up implicit use of lists and types
stop_machine.h: fix implicit use of smp.h for smp_processor_id
of: fix implicit use of errno.h in include/linux/of.h
of_platform.h: delete needless include <linux/module.h>
acpi: remove module.h include from platform/aclinux.h
miscdevice.h: delete unnecessary inclusion of module.h
device_cgroup.h: delete needless include <linux/module.h>
net: sch_generic remove redundant use of <linux/module.h>
net: inet_timewait_sock doesnt need <linux/module.h>
...
Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in
- drivers/media/dvb/frontends/dibx000_common.c
- drivers/media/video/{mt9m111.c,ov6650.c}
- drivers/mfd/ab3550-core.c
- include/linux/dmaengine.h
V4L2_CID_POWER_LINE_FREQUENCY control allows applications to instruct
a driver what is the power line frequency so an appropriate filter
can be used by the device to cancel flicker by compensating the light
intensity ripple. Currently in the menu we have entries for 50 Hz and
60 Hz and for entirely disabling the anti-flicker filter.
However some devices are capable of automatically detecting the
frequency, so add V4L2_CID_POWER_LINE_FREQUENCY_AUTO entry for them.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
These two macros were in module.h but now module.h is no longer
sprayed across every source file imaginable, so the users need
to expicitly call out their use of them.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
The problem tackled in this patch is how to handle volatile autoclusters
correctly. A volatile autocluster is a cluster of related controls where one
control is the control that toggles between manual and auto mode and the other
controls are the values for the manual mode. For example autogain and gain,
autoexposure and exposure, etc.
If the hardware lets you read out the automatically calculated manual values
while in automode, then those manual controls should be marked volatile.
gain value as calculated by the autogain circuitry, then you would mark the
gain control as volatile (i.e. continuously changing).
The question in such use cases is what to do when switching from the auto
mode to the manual mode. Should we switch to the last set manual values or
should the volatile values be copied and used as the initial manual values.
For example: suppose the mode is manual gain and gain is set to 5. Then
autogain is turned on and the gain is set by the hardware to 2. Finally
the user switches back to manual gain. What should the gain be? 2 or 5?
After a long discussion the decisions was made to keep the last value as
calculated by the auto mode (so 2 in the example above).
The reason is that webcams that do such things will adapt themselves to
the current light conditions and when you switch back to manual mode you
expect that you keep the same picture. If you would switch back to old
manual values, then that would give you a suddenly different picture,
which is jarring for the user.
Additionally, this would be difficult to implement in applications that
store and restore the control values at application exit and start.
If you want to keep the old manual values when you switch from auto to
manual, then there would have to be a way for applications to get hold
of those old values while in auto mode, but there isn't.
So this patch will do all the heavy lifting in v4l2-ctrls.c: if you go
from auto mode to manual mode and the manual controls are volatile, then
g_volatile_ctrl will be called to get the current values for the manual
controls before switching to manual mode.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
With the new flag there is no need anymore to have a separate is_volatile
field. Modify all users to use the new flag.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add support for the codec controls to the v4l2 control framework.
[mchehab@redhat.com: Fix merge conflicts and removed some hunks that were
adding blank lines without a good reason]
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add a control class and a set of controls to support LED and Xenon flash
devices. An example of such a device is the adp1653.
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
By default no control events are sent to the application that caused the
control value or flags change (i.e. the control(s) passed to VIDIOC_S_CTRL
or VIDIOC_S_EXT_CTRLS). But if a change in one control causes a change in
another control that was not part of the control(s) in VIDIOC_S_CTRL or
S_EXT_CTRLS, then the application should be notified.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The new values were never copied to userspace due to this copy and paste
error. This was introduced during the rewrite of this part of the code in
commit 3219f8a362640b7e4b7e2187b1094c4e46d85aa0.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Normally no control events will go to the filehandle that called the
VIDIOC_S_CTRL/VIDIOC_S_EXT_CTRLS ioctls. This is to prevent a feedback
loop.
This can now be overridden by setting the new V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK
flag.
Based on suggestions from Mauro Carvalho Chehab <mchehab@redhat.com> and
Laurent Pinchart <laurent.pinchart@ideasonboard.com>.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Split try_or_set_ext_ctrls() into a validate_ctrls() part ('Phase 1')
and merge the second part ('Phase 2') into try_set_ext_ctrls().
This makes a lot more sense and it also does the validation before
trying to try/set the controls.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The implementation of VIDIOC_G/S/TRY_EXT_CTRLS in the control framework has
to figure out which controls in the control list belong to the same cluster.
Since controls belonging to the same cluster need to be handled as a unit,
this is important information.
It did that by going over the controls in the list and for each control that
belonged to a multi-control cluster it would walk the remainder of the list
to try and find controls that belong to that same cluster.
This approach has two disadvantages:
1) it was a potentially quadratic algorithm (although highly unlikely that
it would ever be that bad in practice).
2) it took place with the control handler's lock held.
Since we want to make it possible in the future to change control values
from interrupt context, doing a lot of work while holding a lock is not a
good idea.
In the new code the algorithm is no longer quadratic but linear in the
number of controls in the list. Also, it now can be done beforehand.
Another change that was made was to so the try and set at the same time.
Before when S_TRY_EXT_CTRLS was called it would 'try' the controls first,
and then it would 'set' them. The idea was that any 'try' errors would
prevent the 'set' from happening, thus avoiding having partially set
control lists.
However, this caused more problems than it solved because between the 'try'
and the 'set' changes might have happened, so it had to try a second time,
and since actual controls with a try_ctrl op are very rare (and those that
we have just adjust values and do not return an error), I've decided to
drop that two-stage approach and just combine try and set.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
When sending the SEND_INITIAL event for write-only controls the
V4L2_EVENT_CTRL_CH_VALUE flag should not be set. It's meaningless.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The driver had to decide how many events to allocate when the v4l2_fh struct
was created. It was possible to add more events afterwards, but there was no
way to ensure that you wouldn't miss important events if the event queue
would fill up for that filehandle.
In addition, once there were no more free events, any new events were simply
dropped on the floor.
For the control event in particular this made life very difficult since
control status/value changes could just be missed if the number of allocated
events and the speed at which the application read events was too low to keep
up with the number of generated events. The application would have no idea
what the latest state was for a control since it could have missed the latest
control change.
So this patch makes some major changes in how events are allocated. Instead
of allocating events per-filehandle they are now allocated when subscribing an
event. So for that particular event type N events (determined by the driver)
are allocated. Those events are reserved for that particular event type.
This ensures that you will not miss events for a particular type altogether.
In addition, if there are N events in use and a new event is raised, then
the oldest event is dropped and the new one is added. So the latest event
is always available.
This can be further improved by adding the ability to merge the state of
two events together, ensuring that no data is lost at all. This will be
added in the next patch.
This also makes it possible to allow the user to determine the number of
events that will be allocated. This is not implemented at the moment, but
would be trivial.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Sylwester Nawrocki