kernel/linux.git/include/sound/control.h, branch v6.1.168

ALSA: control: add snd_ctl_rename()

2022-10-21T06:17:08+00:00

Add a snd_ctl_rename() function that takes care of updating the control hash entries for callers that already have the relevant struct snd_kcontrol at hand and hold the control write lock (or simply haven't registered the card yet). Fixes: c27e1efb61c5 ("ALSA: control: Use xarray for faster lookups") Cc: stable@vger.kernel.org Signed-off-by: Maciej S. Szmigiero Link: https://lore.kernel.org/r/4170b71117ea81357a4f7eb8410f7cde20836c70.1666296963.git.maciej.szmigiero@oracle.com Signed-off-by: Takashi Iwai

ALSA: control: Use deferred fasync helper

2022-07-29T10:57:12+00:00

For avoiding the potential deadlock via kill_fasync() call, use the new fasync helpers to defer the invocation from the control API. Note that it's merely a workaround. Another note: although we haven't received reports about the deadlock with the control API, the deadlock is still potentially possible, and it's better to align the behavior with other core APIs (PCM and timer); so let's move altogether. Link: https://lore.kernel.org/r/20220728125945.29533-5-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: control: Rename CONFIG_SND_CTL_VALIDATION to CONFIG_SND_CTL_DEBUG

2022-06-15T05:45:27+00:00

The purpose of CONFIG_SND_CTL_VALIDATION is rather to enable the debugging feature for the control API. The validation is only a part of it. Let's rename it to be more explicit and intuitive. While we're at it, let's advertise, give more comment to recommend this feature for development in the kconfig help text. Link: https://lore.kernel.org/r/20220609120219.3937-3-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: control - add generic LED trigger module as the new control layer

2021-03-30T13:33:58+00:00

The recent laptops have usually two LEDs assigned to reflect the speaker and microphone mute state. This implementation adds a tiny layer on top of the control API which calculates the state for those LEDs using the driver callbacks. Two new access flags are introduced to describe the controls which affects the audio path settings (an easy code change for drivers). The LED resource can be shared with multiple sound cards with this code. The user space controls may be added to the state chain on demand, too. This code should replace the LED code in the HDA driver and add a possibility to easy extend the other drivers (ASoC codecs etc.). Signed-off-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20210317172945.842280-4-perex@perex.cz Signed-off-by: Takashi Iwai

ALSA: control - add layer registration routines

2021-03-30T13:33:13+00:00

The layer registration allows to handle an extra functionality on top of the control API. It can be used for the audio LED control for example. Signed-off-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20210317172945.842280-3-perex@perex.cz Signed-off-by: Takashi Iwai

ALSA: control - introduce snd_ctl_notify_one() helper

2021-03-30T13:33:03+00:00

This helper is required for the following generic LED mute patch. The helper also simplifies some other functions. Signed-off-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20210317172945.842280-2-perex@perex.cz Signed-off-by: Takashi Iwai

ALSA: make snd_kcontrol_new name a normal string

2020-10-26T19:28:59+00:00

When building with W=2, there are lots of warnings about the snd_kcontrol_new name field being an array of 'unsigned char' but initialized to a string: include/sound/soc.h:93:48: warning: pointer targets in initialization of 'const unsigned char *' from 'char *' differ in signedness [-Wpointer-sign] Make it a regular 'char *' to avoid flooding the build log with this. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Arnd Bergmann Link: https://lore.kernel.org/r/20201026165715.3723704-1-arnd@kernel.org Signed-off-by: Takashi Iwai

ALSA: Replace the word "slave" in vmaster API

2020-07-20T08:10:47+00:00

Follow the recent inclusive terminology guidelines and replace the word "slave" in vmaster API. I chose the word "follower" at this time since it seems fitting for the purpose. Note that the word "master" is kept in API, since it refers rather to audio master volume control. Also, while we're at it, a typo in comments is corrected, too. Link: https://lore.kernel.org/r/20200717154517.27599-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: Replace zero-length array with flexible-array

2020-05-07T20:30:36+00:00

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20200507192223.GA16335@embeddedor Signed-off-by: Takashi Iwai

ALSA: control: Add verification for kctl accesses

2020-01-04T08:37:59+00:00

The current implementation of ALSA control API fully relies on the callbacks of each driver, and there is no verification of the values passed via API. This patch is an attempt to improve the situation slightly by adding the validation code for the values stored via info and get callbacks. The patch adds a new kconfig, CONFIG_SND_CTL_VALIDATION. It depends on CONFIG_SND_DEBUG and off as default since the validation would require a slight overhead including the additional call of info callback at each get callback invocation. When this config is enabled, the values stored by each info callback invocation are verified, namely: - Whether the info type is valid - Whether the number of enum items is non-zero - Whether the given info count is within the allowed boundary Similarly, the values stored at each get callback are verified as well: - Whether the values are within the given range - Whether the values are aligned with the given step - Whether any further changes are seen in the data array over the given info count The last point helps identifying a possibly invalid data type access, typically a case where the info callback declares the type being SNDRV_CTL_ELEM_TYPE_ENUMERATED while the get/put callbacks store the values in value.integer.value[] array. When a validation fails, the ALSA core logs an error message including the device and the control ID, and the API call also returns an error. So, with the new validation turned on, the driver behavior difference may be visible on user-space, too -- it's intentional, though, so that we can catch an error more clearly. The patch also introduces a new ctl access type, SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK. A driver may pass this flag with other access bits to indicate that the ctl element won't be verified. It's useful when a driver code is specially written to access the data greater than info->count size by some reason. For example, this flag is actually set now in HD-audio HDMI codec driver which needs to clear the data array in the case of the disconnected monitor. Also, the PCM channel-map helper code is slightly modified to avoid the false-positive hit by this validation code, too. Link: https://lore.kernel.org/r/20200104083556.27789-1-tiwai@suse.de Signed-off-by: Takashi Iwai