In documentation, there're two ways relevant to the identifier of control
element. However, the case of combination has the lack of parameters.
This commit improves documentation in this point.
Fixes: f3c24de8c0 ("ctl: add an overview for design of ALSA control interface")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Looks like the documented behaviour was broken in commit 1ba513f9 in
2006, with the introduction of multiple fields.
I've chosen to match the described behaviour. Prior to this patch,
using namehint could be made to work by exploiting the lack of escaping
of the "name", populating the other fields:
"plug:front|DESCDo all conversions for front speakers"
rather than that which is documented and presumed to be the intention
for asoundrc files:
"plug:front|Do all conversions for front speakers"
Everything seems to strongly suggest nobody is using this feature; I can
find no working examples through a web search and probably someone
would have hit this bug. It's not documented in configuration, only in
the snd_device_name_hint() call. So it would probably clutter things to
provide compatibility for the old behaviour.
I have found it to be very useful since working in Chromium, where it is
the only way to expose chosen ALSA devices to web applications.
A temporary buffer is required to null-terminate the string. I see no
use of alloca() in the code, presumably to avoid unbounded stack size.
So memory is allocated on the heap.
Signed-off-by: Mark Hills <mark@xwax.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Ths "namehint" is a list, and there doesn't seem to have been any
history where the separator would be a colon.
Signed-off-by: Mark Hills <mark@xwax.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Using a fixed bound of 128 means that too many values may be set for an
INTEGER64 type and that any elements past 128 are out of reach for BYTE
type controls.
Derive the maximum number of elements from the type so that the full
range is parsed for all types.
Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
In commit b906db19ef, the snd_dlopen()
implements the automatic lookup to the ALSA_PLUGIN_DIR directory.
It is not necessary to add the absolute paths in callers now.
The plugin names are also searched in ld.so.conf paths as the fallback now,
but it should not be a big problem.
BugLink: https://github.com/alsa-project/alsa-lib/issues/34
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
The dimen fields of control element has been deprecated, and it's
finally dropped in kernel 5.6 ABI definition. Remove the
corresponding accesses in alsa-lib code.
As of this patch, it's disabled via ifdef, just to be sure. The
disabled code should be removed in a later stage as a cleanup.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
When seccomp policy is applied to filter ioctl syscall with
SNDRV_CTL_IOCTL_TLV_COMMAND, SNDRV_CTL_IOCTL_TLV_READ and
SNDRV_CTL_IOCTL_TLV_WRITE in whiltelist, alsa-lib still breaks
in at snd_ctl_hw_elem_tlv().
The problem behind is because ioctl() takes unsigned long cmd
argument, and the signed bit of local int variable could cause
0xff bytes appended after casted to unsigned long.
In kernel, seccomp data struct takes 64 bits argument to check
against seccomp rules, these unexpected 0xff bytes could make
the rule check fail.
Fix the problem by passing unsigned int to ioctl.
Signed-off-by: Hsin-Yu Chao <hychao@chromium.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
A series of SNDRV_CTL_TLVO_XXX macro was introduced for position offset
of TLV data. This commit applies a code optimization.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
A series of SNDRV_CTL_TLVO_XXX macro was introduced for position offset
of TLV data. This commit applies a code optimization.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The multiply defined versioned symbols have to be called with
INTERNAL() wrapper.
Add the missing declarations of the internal forms of
snd_ctl_elem_info_get_dimension*() in the local header, and use them
in the (still remaining) callers in alisp.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In ALSA control interface in asound.h, 'struct snd_ctl_elem_info' has
'dimen' member to deliver information for multi-dimensional array, however
there's no common way to handle the member. As a result, drivers can
force userspace applications to handle the information by inconsistent
ways.
This issue was reported by a commit 51db452df07b ('Revert "ALSA: echoaudio:
purge contradictions between dimension matrix members and total number of
members"') to Linux kernel. As a result of discussion at Linux
miniconference 2017, usage of 'dimen' member of 'struct snd_ctl_elem_info'
is going to be deprecated for future removal.
A removal of kernel interface can cause regression issues. However no ALSA
driver in kernel land except for 'echoaudio' series utilizes this feature.
Actually it's reasonable to assume that 'echomixer' program is an unique
consumer of the interface in user land and the removal rarely brings any
impact to user land.
This commit deprecates some APIs corresponding to the kernel interface. The
kernel interface is kept till Linux kernel v4.20 at least, but actual
timing of removal is not fixed yet. After that, these APIs may also be
removed at a reasonable timing.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The snd_ctl_ext_callback::read_event() callback is only optional
if no poll descriptor was given via
snd_ctl_ext_t::poll_fd
or
snd_ctl_ext_callback::snd_ctl_ext_poll_descriptors().
If a poll descriptor is given the
snd_ctl_ext_callback::read_event()
callback has also to be defined
because there is no minigful default behavior.
This callback will be called when ever the poll() on
the file descriptor indicates that there is an event pending.
Therefore returning a 0 which indicates that there is no event makes no
sense.
Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
According POSIX[1] and linux manpage[2] the include is poll.h, not
sys/poll.h.
This fixes the he following compiler warning when build with musl libc:
/usr/include/sys/poll.h:1:2: warning: #warning redirecting incorrect #include <sys/poll.h> to <poll.h> [-Wcpp]
#warning redirecting incorrect #include <sys/poll.h> to <poll.h>
^~~~~~~
Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
From my misunderstanding, some explanations are wrong. This commit
corrects them.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The documentation gives no hints to users about format of TLV data.
This commit add hints to construct/parse the information.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
A commit fe1b08803d ("ctl: improve API documentation for threshold level
operations") changes documentations for some TLV-related APIs with wrong
explanations.
This commit fix it with better explanations.
Fixes: fe1b08803d ("ctl: improve API documentation for threshold level operations")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Usage of assert() is not better practice of programming as shared library
APIs. They should return appropriate error code to promote applications to
handle error state.
This commit applies condition statements with return value of -EINVAL,
instead of assert(). As a backward compatibility for existent applications,
old APIs still call assert().
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In this development period, some APIs have already been added. Most of
them are to add an element set, while their names are not so appropriate
against their feature. This is due to following to names of old APIs.
This commit renames them.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
I forgot it when committing to the API.
Fixes: 16812b70daeb('ctl: add an API to set dimension levels to element information')
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In ALSA control core, when several events occurs for an element, they're
represented bit mask (struct snd_ctl_event.data.elem.mask). Thus userspace
applications can handles these events separately in one I/O operation.
There's an exception; removal event. This is represented by all of bits in
the mask. Therefore, when a removal event occurs for an element, all of
queued events for the element are overwritten.
This works worse for a combination of applications which add/remove control
elements and applications which keep a cache of elements. For example,
let's assume a case that:
1.some elements are added by ioctl(SNDRV_CTL_IOCTL_ELEM_ADD).
2.ALSA control core handles the request and queues 'add' event.
3.applications don't read the event yet.
4.the elements are removed by ioctl(SNDRV_CTL_IOCTL_ELEM_REMOVE)
5.ALSA control core handles the request and queues 'removal' event by
overwriting queued events.
6.applications read the event at last.
7.the applications cannot find removed elements in their cache data.
Especially, when applications use hctl interface of ALSA userspace library,
this situation occurs because the interface is designed to keep element
cache implicitly inner the library. PulseAudio is such an application. When
executing a test program of ALSA library (test/user-ctl-element-set.c),
pulseaudio process aborts due to assertion at calls of
snd_hctl_handle_events().
The rule to represent events is in ALSA kernel/userspace interfaces
(UAPI header) and it's difficult to improve the rule. Therefore,
developers should pay enough attention to the fact that userspace
applications can receive removal events for elements which are not
notified with 'add' event.
For this reason, this commit removes assertion from event handler of ALSA
hctl API.
CC: pulseaudio-discuss@lists.freedesktop.org
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Currently, documentation of APIs to add an element set describes causes of
errors partly. But it gives an opinion to describe them thoroughly. This
is not good for users.
This commit changes the documentation so that it partly describes the
causes.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Linux 4.7 or former have no validator of dimension information. This can
causes an issue related to user-defined element set. For example, When
calculated total members in multi-dimensional matrix is larger than actual
capacity of snd_ctl_elem_value_t, processes to handle the element can
cause buffer-over-run.
For backward portability of this userspace library, this commit adds a
validator of dimension information. When userspace applications give
invalid dimension information to APIs to add element set, they receive
-EINVAL.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In a former commit, 'struct snd_ctl_elem_info' is used as a 'container' to
transfer extra fields of element information for APIs to add an element
set. The extra fields should be filled in advance of call of the APIs.
Currently, dimension level is in the extra fields and no APIs to set it.
This commit adds an API to set dimension level to the information
structure. This API is expected to be used in advance of usage of APIs
to add an element set, for nothing others. When the information structure
is extended in future, then the similar APIs shall be added for the new
feature.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In ALSA control feature, information of an element includes extra fields
to type-specific parameters; i.e. dimension. The fields can be extended in
future.
Meanwhile, current APIs to add user-defined element set can not support
such an extended fields. This may cause inconveniences in future.
This commit supports the fields, by changing APIs for element set.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Second argument of these functions has three different names in
documentation/header/code (obj/control/value). This easily causes users'
confusion.
This commit applies consistent names for the arguments.
Fixes: 90020c05f8 ('ctl: improve comments for handling element data')
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Inner this library, layouts of all structures are public. At a compilation
time, each size of the structures can be calculated. It means that we can
use automatic variable instead of calling alloca(3) to program this
library because in both ways storages are kept on stack frame of process
VMA. Besides, the usage of automatic variables requires less instructions
than calls of alloca(3). Furthermore, alloca(3) is not described in any
C language standards.
This commit replaces calls of alloca(3) just for structures with automatic
variables, for control features.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In ALSA kernel/userspace interfaces, 'struct snd_ctl_elem_info' has a
'dimension' parameter. This parameter consists of an array with four
elements. Each element represents the number of members in corresponding
dimension level to construct matrix.
In current implementation, a get function, 'snd_ctl_elem_info_get_dimension()'
is hardcoded to return zero to level 4, against actual value. This commit fixes
the bug.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In alsa-lib, threshold level operations require an array of unsigned-int
members, while there's little explanation about how to fill it. To usual
developers such as me, they're quite hard to understand.
This commit adds a few comment for easy understanding about how to use
the APIs.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
ALSA ctl feature includes threshold level feature. This is introduced in
2006, and there's little resources about it.
This commit adds a simple explanation about the feature.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In former commit, userspace library gets some APIs for element set. Some
existed functions can be simple wrappers of them.
This commit changes these APIs as wrapper functions. Additionally, this
commit also adds local variables for identical information of elements.
This modification is important to keep API consistency.
Some old APIs to add an element have id variables with const type
qualifier, while some new APIs to add element set changes the content of
given parameters. This comes from a change in Linux kernel 4.1.
In this commit [1], in-kernel implementation fills all fields of identical
data in userspace. As a result, when adding a new element set, userspace
applications can get an identical data for the first element in the set.
This lost the semantics of const type qualifier in userspace.
[1] http://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound/core?id=cab2ed7474bffafd2a68a885e03b85526194abcd
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
In ALSA control core, it's not allowed to an element set of IEC 958 type
to have several elements. Therefore, consecutive patchset doesn't touch an
API to add an element of IEC958 type. However, it's better to supplement
comments for the API.
This commit do it.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
