* [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing values of multiple controls in one go (at once)
[not found] <CGME20170202031525epcas1p2164b4ca25afe9fb5cd418d004da961f5@epcas1p2.samsung.com>
@ 2017-02-02 3:14 ` Satendra Singh Thakur
2017-02-02 3:45 ` Takashi Sakamoto
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Satendra Singh Thakur @ 2017-02-02 3:14 UTC (permalink / raw)
To: alsa-devel
Cc: perex, tiwai, o-takashi, linux-kernel, hemanshu.s, nishant.s4,
ycheon.song, satendra singh thakur
From: satendra singh thakur <satendra.t@samsung.com>
-Added 2 ioctls in alsa driver's control interface
-Added an ioctl to read values of multiple elements at once
-Added an ioctl to write values of multiple elements at once
-In the absence of above ioctls user needs to call N ioctls to
read/write value of N elements which requires N context switches
-Proposed ioctls will allow accessing N elements' values in a single
context switch
-Above mentioned ioctl will be useful for alsa utils such as amixer
which reads all controls of given sound card
Signed-off-by: Satendra Singh Thakur <satendra.t@samsung.com>
---
include/uapi/sound/asound.h | 8 +++++
sound/core/control.c | 69 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 77 insertions(+)
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
index be353a7..a0dcee7 100644
--- a/include/uapi/sound/asound.h
+++ b/include/uapi/sound/asound.h
@@ -948,6 +948,11 @@ struct snd_ctl_tlv {
unsigned int length; /* in bytes aligned to 4 */
unsigned int tlv[0]; /* first TLV */
};
+/*Struct to read/write multiple element values */
+struct snd_ctl_elem_values {
+ unsigned int num_vals;/* Number of values*/
+ struct snd_ctl_elem_value *pvals;/* Pointer to the array of values */
+};
#define SNDRV_CTL_IOCTL_PVERSION _IOR('U', 0x00, int)
#define SNDRV_CTL_IOCTL_CARD_INFO _IOR('U', 0x01, struct snd_ctl_card_info)
@@ -974,6 +979,9 @@ struct snd_ctl_tlv {
#define SNDRV_CTL_IOCTL_RAWMIDI_PREFER_SUBDEVICE _IOW('U', 0x42, int)
#define SNDRV_CTL_IOCTL_POWER _IOWR('U', 0xd0, int)
#define SNDRV_CTL_IOCTL_POWER_STATE _IOR('U', 0xd1, int)
+/*Multipe controls' values read and write*/
+#define SNDRV_CTL_IOCTL_ELEMS_READ _IOWR('U', 0xe0, struct snd_ctl_elem_values)
+#define SNDRV_CTL_IOCTL_ELEMS_WRITE _IOWR('U', 0xe1, struct snd_ctl_elem_values)
/*
* Read interface.
diff --git a/sound/core/control.c b/sound/core/control.c
index fb096cb..d60dc98 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -942,6 +942,7 @@ static int snd_ctl_elem_read_user(struct snd_card *card,
return result;
}
+
static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
struct snd_ctl_elem_value *control)
{
@@ -1000,6 +1001,70 @@ static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
return result;
}
+/**
+ * snd_ctl_elems_rw_user - Read/Write values of more than one element,
+ * one by one
+ * @card: the card to which element belongs to
+ * @pucontrols: user-space pointer to struct snd_ctl_elem_values
+ * @write_flag: this flag distinguises write or read type request
+ *
+ * This function reads/writes the value of controls with the given IDs
+ * of the same card
+ * Return: On full/partial success, It returns number of successful
+ * controls read/written.
+ * On failure, it returns appropriate error
+ */
+static int snd_ctl_elems_rw_user(struct snd_ctl_file *file,
+ struct snd_ctl_elem_values __user *pucontrols,
+ bool write_flag)
+{
+ struct snd_ctl_elem_values controls;
+ struct snd_ctl_elem_value control;
+ struct snd_ctl_elem_value __user *puvals;
+ struct snd_card *card = file->card;
+ int result;
+ int vals;
+ int controls_count = 0;
+
+ if (copy_from_user(&controls, pucontrols, sizeof(controls)))
+ return -EFAULT;
+ if (!controls.num_vals || controls.num_vals > card->controls_count)
+ return -EINVAL;
+ /*assign user-space pointer**/
+ puvals = (struct snd_ctl_elem_value __user *) controls.pvals;
+ for (vals = 0; vals < controls.num_vals; vals++) {
+ if (copy_from_user(&control, puvals + vals, sizeof(control)))
+ return -EFAULT;
+ snd_power_lock(card);
+ result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
+ if (result >= 0) {
+ if (write_flag == true)
+ result = snd_ctl_elem_write(card, file,
+ &control);
+ else
+ result = snd_ctl_elem_read(card, &control);
+ }
+ snd_power_unlock(card);
+ if (result < 0) {
+ /**If control failed to set/get
+ * inform user by sending back -1 in reserved field
+ * so that one can try again for failed elements
+ */
+ control.reserved[0] = (unsigned char) -1;
+ pr_err("ALSA: control: snd_ctl_elem_write/read failed\
+ for control name = %s\n", control.id.name);
+ } else {
+ controls_count++;
+ }
+ if (copy_to_user(puvals + vals, &control, sizeof(control)))
+ return -EFAULT;
+ }
+ pr_debug("ALSA: control: Num values successfully read/written %u\n",\
+ controls_count);
+ /**Return successful control count to user**/
+ return controls_count;
+}
+
static int snd_ctl_elem_lock(struct snd_ctl_file *file,
struct snd_ctl_elem_id __user *_id)
{
@@ -1515,8 +1580,12 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
return snd_ctl_elem_info_user(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_READ:
return snd_ctl_elem_read_user(card, argp);
+ case SNDRV_CTL_IOCTL_ELEMS_READ:
+ return snd_ctl_elems_rw_user(ctl, argp, false);
case SNDRV_CTL_IOCTL_ELEM_WRITE:
return snd_ctl_elem_write_user(ctl, argp);
+ case SNDRV_CTL_IOCTL_ELEMS_WRITE:
+ return snd_ctl_elems_rw_user(ctl, argp, true);
case SNDRV_CTL_IOCTL_ELEM_LOCK:
return snd_ctl_elem_lock(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
--
1.7.9.5
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing values of multiple controls in one go (at once)
2017-02-02 3:14 ` [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing values of multiple controls in one go (at once) Satendra Singh Thakur
@ 2017-02-02 3:45 ` Takashi Sakamoto
2017-02-03 7:24 ` Takashi Iwai
2017-02-02 17:22 ` [alsa-devel] " Clemens Ladisch
2017-02-03 5:28 ` Satendra Singh Thakur
2 siblings, 1 reply; 5+ messages in thread
From: Takashi Sakamoto @ 2017-02-02 3:45 UTC (permalink / raw)
To: Satendra Singh Thakur, alsa-devel
Cc: perex, tiwai, linux-kernel, hemanshu.s, nishant.s4, ycheon.song
Hi,
On Feb 2 2017 12:14, Satendra Singh Thakur wrote:
> From: satendra singh thakur <satendra.t@samsung.com>
>
> -Added 2 ioctls in alsa driver's control interface
> -Added an ioctl to read values of multiple elements at once
> -Added an ioctl to write values of multiple elements at once
> -In the absence of above ioctls user needs to call N ioctls to
> read/write value of N elements which requires N context switches
> -Proposed ioctls will allow accessing N elements' values in a single
> context switch
> -Above mentioned ioctl will be useful for alsa utils such as amixer
> which reads all controls of given sound card
>
> Signed-off-by: Satendra Singh Thakur <satendra.t@samsung.com>
> ---
> include/uapi/sound/asound.h | 8 +++++
> sound/core/control.c | 69 +++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 77 insertions(+)
I'm _strongly_ interested in your two patches, because it has a
potentiality to purge ASoC abuse of TLV feature, which was introduced in
2014 with a bad reviewing process.
Unfortunately, I have a short vacation in this weekend, so my reviewing
is postponed to next week, sorry...
Anyway, in next time, please post them as one patchset so that reviewers
easily pick them up. 'git format-patch' and 'git send-email' will assist
you.
> diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
> index be353a7..a0dcee7 100644
> --- a/include/uapi/sound/asound.h
> +++ b/include/uapi/sound/asound.h
> @@ -948,6 +948,11 @@ struct snd_ctl_tlv {
> unsigned int length; /* in bytes aligned to 4 */
> unsigned int tlv[0]; /* first TLV */
> };
> +/*Struct to read/write multiple element values */
> +struct snd_ctl_elem_values {
> + unsigned int num_vals;/* Number of values*/
> + struct snd_ctl_elem_value *pvals;/* Pointer to the array of values */
> +};
>
> #define SNDRV_CTL_IOCTL_PVERSION _IOR('U', 0x00, int)
> #define SNDRV_CTL_IOCTL_CARD_INFO _IOR('U', 0x01, struct snd_ctl_card_info)
> @@ -974,6 +979,9 @@ struct snd_ctl_tlv {
> #define SNDRV_CTL_IOCTL_RAWMIDI_PREFER_SUBDEVICE _IOW('U', 0x42, int)
> #define SNDRV_CTL_IOCTL_POWER _IOWR('U', 0xd0, int)
> #define SNDRV_CTL_IOCTL_POWER_STATE _IOR('U', 0xd1, int)
> +/*Multipe controls' values read and write*/
> +#define SNDRV_CTL_IOCTL_ELEMS_READ _IOWR('U', 0xe0, struct snd_ctl_elem_values)
> +#define SNDRV_CTL_IOCTL_ELEMS_WRITE _IOWR('U', 0xe1, struct snd_ctl_elem_values)
>
> /*
> * Read interface.
> diff --git a/sound/core/control.c b/sound/core/control.c
> index fb096cb..d60dc98 100644
> --- a/sound/core/control.c
> +++ b/sound/core/control.c
> @@ -942,6 +942,7 @@ static int snd_ctl_elem_read_user(struct snd_card *card,
> return result;
> }
>
> +
> static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
> struct snd_ctl_elem_value *control)
> {
> @@ -1000,6 +1001,70 @@ static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
> return result;
> }
>
> +/**
> + * snd_ctl_elems_rw_user - Read/Write values of more than one element,
> + * one by one
> + * @card: the card to which element belongs to
> + * @pucontrols: user-space pointer to struct snd_ctl_elem_values
> + * @write_flag: this flag distinguises write or read type request
> + *
> + * This function reads/writes the value of controls with the given IDs
> + * of the same card
> + * Return: On full/partial success, It returns number of successful
> + * controls read/written.
> + * On failure, it returns appropriate error
> + */
> +static int snd_ctl_elems_rw_user(struct snd_ctl_file *file,
> + struct snd_ctl_elem_values __user *pucontrols,
> + bool write_flag)
> +{
> + struct snd_ctl_elem_values controls;
> + struct snd_ctl_elem_value control;
> + struct snd_ctl_elem_value __user *puvals;
> + struct snd_card *card = file->card;
> + int result;
> + int vals;
> + int controls_count = 0;
> +
> + if (copy_from_user(&controls, pucontrols, sizeof(controls)))
> + return -EFAULT;
> + if (!controls.num_vals || controls.num_vals > card->controls_count)
> + return -EINVAL;
> + /*assign user-space pointer**/
> + puvals = (struct snd_ctl_elem_value __user *) controls.pvals;
> + for (vals = 0; vals < controls.num_vals; vals++) {
> + if (copy_from_user(&control, puvals + vals, sizeof(control)))
> + return -EFAULT;
> + snd_power_lock(card);
> + result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
> + if (result >= 0) {
> + if (write_flag == true)
> + result = snd_ctl_elem_write(card, file,
> + &control);
> + else
> + result = snd_ctl_elem_read(card, &control);
> + }
> + snd_power_unlock(card);
> + if (result < 0) {
> + /**If control failed to set/get
> + * inform user by sending back -1 in reserved field
> + * so that one can try again for failed elements
> + */
> + control.reserved[0] = (unsigned char) -1;
> + pr_err("ALSA: control: snd_ctl_elem_write/read failed\
> + for control name = %s\n", control.id.name);
> + } else {
> + controls_count++;
> + }
> + if (copy_to_user(puvals + vals, &control, sizeof(control)))
> + return -EFAULT;
> + }
> + pr_debug("ALSA: control: Num values successfully read/written %u\n",\
> + controls_count);
> + /**Return successful control count to user**/
> + return controls_count;
> +}
> +
> static int snd_ctl_elem_lock(struct snd_ctl_file *file,
> struct snd_ctl_elem_id __user *_id)
> {
> @@ -1515,8 +1580,12 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
> return snd_ctl_elem_info_user(ctl, argp);
> case SNDRV_CTL_IOCTL_ELEM_READ:
> return snd_ctl_elem_read_user(card, argp);
> + case SNDRV_CTL_IOCTL_ELEMS_READ:
> + return snd_ctl_elems_rw_user(ctl, argp, false);
> case SNDRV_CTL_IOCTL_ELEM_WRITE:
> return snd_ctl_elem_write_user(ctl, argp);
> + case SNDRV_CTL_IOCTL_ELEMS_WRITE:
> + return snd_ctl_elems_rw_user(ctl, argp, true);
> case SNDRV_CTL_IOCTL_ELEM_LOCK:
> return snd_ctl_elem_lock(ctl, argp);
> case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
Thanks
Takashi Sakamoto
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [alsa-devel] [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing values of multiple controls in one go (at once)
2017-02-02 3:14 ` [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing values of multiple controls in one go (at once) Satendra Singh Thakur
2017-02-02 3:45 ` Takashi Sakamoto
@ 2017-02-02 17:22 ` Clemens Ladisch
2017-02-03 5:28 ` Satendra Singh Thakur
2 siblings, 0 replies; 5+ messages in thread
From: Clemens Ladisch @ 2017-02-02 17:22 UTC (permalink / raw)
To: Satendra Singh Thakur
Cc: alsa-devel, ycheon.song, tiwai, linux-kernel, nishant.s4,
hemanshu.s, o-takashi
Satendra Singh Thakur wrote:
> -Added an ioctl to read values of multiple elements at once
> -Added an ioctl to write values of multiple elements at once
> -In the absence of above ioctls user needs to call N ioctls to
> read/write value of N elements which requires N context switches
And why are these N context switches a problem?
> -Above mentioned ioctl will be useful for alsa utils such as amixer
> which reads all controls of given sound card
Is there a noticeable difference?
Regards,
Clemens
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing values of multiple controls in one go (at once)
2017-02-02 3:14 ` [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing values of multiple controls in one go (at once) Satendra Singh Thakur
2017-02-02 3:45 ` Takashi Sakamoto
2017-02-02 17:22 ` [alsa-devel] " Clemens Ladisch
@ 2017-02-03 5:28 ` Satendra Singh Thakur
2 siblings, 0 replies; 5+ messages in thread
From: Satendra Singh Thakur @ 2017-02-03 5:28 UTC (permalink / raw)
To: Takashi Sakamoto, alsa-devel
Cc: linux-kernel, Nishant Singh, tiwai, HEMANSHU SRIVASTAVA
[-- Attachment #1.1: Type: text/plain, Size: 7482 bytes --]
Hello Mr Takashi,
Thanks for positive comments.
I have combined these patches into single one and submitted again
(Fixed few doxygen comments and stack frame related warning ).
Thanks
-Satendra
--------- Original Message ---------
Sender : Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date : 2017-02-02 09:15 (GMT+5:30)
Title : Re: [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing
values of multiple controls in one go (at once)
Hi,
On Feb 2 2017 12:14, Satendra Singh Thakur wrote:
> From: satendra singh thakur <satendra.t@samsung.com>
>
> -Added 2 ioctls in alsa driver's control interface
> -Added an ioctl to read values of multiple elements at once
> -Added an ioctl to write values of multiple elements at once
> -In the absence of above ioctls user needs to call N ioctls to
> read/write value of N elements which requires N context switches
> -Proposed ioctls will allow accessing N elements' values in a single
> context switch
> -Above mentioned ioctl will be useful for alsa utils such as amixer
> which reads all controls of given sound card
>
> Signed-off-by: Satendra Singh Thakur <satendra.t@samsung.com>
> ---
> include/uapi/sound/asound.h | 8 +++++
> sound/core/control.c | 69 ++++++++++++++++++++++++++++++++++++++++++
+
> 2 files changed, 77 insertions(+)
I'm _strongly_ interested in your two patches, because it has a
potentiality to purge ASoC abuse of TLV feature, which was introduced in
2014 with a bad reviewing process.
Unfortunately, I have a short vacation in this weekend, so my reviewing
is postponed to next week, sorry...
Anyway, in next time, please post them as one patchset so that reviewers
easily pick them up. 'git format-patch' and 'git send-email' will assist
you.
> diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
> index be353a7..a0dcee7 100644
> --- a/include/uapi/sound/asound.h
> +++ b/include/uapi/sound/asound.h
> @@ -948,6 +948,11 @@ struct snd_ctl_tlv {
> unsigned int length; /* in bytes aligned to 4 */
> unsigned int tlv[0]; /* first TLV */
> };
> +/*Struct to read/write multiple element values */
> +struct snd_ctl_elem_values {
> + unsigned int num_vals;/* Number of values*/
> + struct snd_ctl_elem_value *pvals;/* Pointer to the array of values */
> +};
>
> #define SNDRV_CTL_IOCTL_PVERSION _IOR('U', 0x00, int)
> #define SNDRV_CTL_IOCTL_CARD_INFO _IOR('U', 0x01, struct snd_ctl_card_info
)
> @@ -974,6 +979,9 @@ struct snd_ctl_tlv {
> #define SNDRV_CTL_IOCTL_RAWMIDI_PREFER_SUBDEVICE _IOW('U', 0x42, int)
> #define SNDRV_CTL_IOCTL_POWER _IOWR('U', 0xd0, int)
> #define SNDRV_CTL_IOCTL_POWER_STATE _IOR('U', 0xd1, int)
> +/*Multipe controls' values read and write*/
> +#define SNDRV_CTL_IOCTL_ELEMS_READ _IOWR('U', 0xe0, struct snd_ctl_elem_val
ues)
> +#define SNDRV_CTL_IOCTL_ELEMS_WRITE _IOWR('U', 0xe1, struct snd_ctl_elem_val
ues)
>
> /*
> * Read interface.
> diff --git a/sound/core/control.c b/sound/core/control.c
> index fb096cb..d60dc98 100644
> --- a/sound/core/control.c
> +++ b/sound/core/control.c
> @@ -942,6 +942,7 @@ static int snd_ctl_elem_read_user(struct snd_card *card,
> return result;
> }
>
> +
> static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *fil
e,
> struct snd_ctl_elem_value *control)
> {
> @@ -1000,6 +1001,70 @@ static int snd_ctl_elem_write_user(struct snd_ctl_file
*file,
> return result;
> }
>
> +/**
> + * snd_ctl_elems_rw_user - Read/Write values of more than one element,
> + * one by one
> + * @card: the card to which element belongs to
> + * @pucontrols: user-space pointer to struct snd_ctl_elem_values
> + * @write_flag: this flag distinguises write or read type request
> + *
> + * This function reads/writes the value of controls with the given IDs
> + * of the same card
> + * Return: On full/partial success, It returns number of successful
> + * controls read/written.
> + * On failure, it returns appropriate error
> + */
> +static int snd_ctl_elems_rw_user(struct snd_ctl_file *file,
> + struct snd_ctl_elem_values __user *pucontrols,
> + bool write_flag)
> +{
> + struct snd_ctl_elem_values controls;
> + struct snd_ctl_elem_value control;
> + struct snd_ctl_elem_value __user *puvals;
> + struct snd_card *card = file->card;
> + int result;
> + int vals;
> + int controls_count = 0;
> +
> + if (copy_from_user(&controls, pucontrols, sizeof(controls)))
> + return -EFAULT;
> + if (!controls.num_vals || controls.num_vals > card->controls_count)
> + return -EINVAL;
> + /*assign user-space pointer**/
> + puvals = (struct snd_ctl_elem_value __user *) controls.pvals;
> + for (vals = 0; vals < controls.num_vals; vals++) {
> + if (copy_from_user(&control, puvals + vals, sizeof(control)))
> + return -EFAULT;
> + snd_power_lock(card);
> + result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
> + if (result >= 0) {
> + if (write_flag == true)
> + result = snd_ctl_elem_write(card, file,
> + &control);
> + else
> + result = snd_ctl_elem_read(card, &control);
> + }
> + snd_power_unlock(card);
> + if (result < 0) {
> + /**If control failed to set/get
> + * inform user by sending back -1 in reserved field
> + * so that one can try again for failed elements
> + */
> + control.reserved[0] = (unsigned char) -1;
> + pr_err("ALSA: control: snd_ctl_elem_write/read failed\
> + for control name = %s\n", control.id.name);
> + } else {
> + controls_count++;
> + }
> + if (copy_to_user(puvals + vals, &control, sizeof(control)))
> + return -EFAULT;
> + }
> + pr_debug("ALSA: control: Num values successfully read/written %u\n",\
> + controls_count);
> + /**Return successful control count to user**/
> + return controls_count;
> +}
> +
> static int snd_ctl_elem_lock(struct snd_ctl_file *file,
> struct snd_ctl_elem_id __user *_id)
> {
> @@ -1515,8 +1580,12 @@ static long snd_ctl_ioctl(struct file *file, unsigned i
nt cmd, unsigned long arg
> return snd_ctl_elem_info_user(ctl, argp);
> case SNDRV_CTL_IOCTL_ELEM_READ:
> return snd_ctl_elem_read_user(card, argp);
> + case SNDRV_CTL_IOCTL_ELEMS_READ:
> + return snd_ctl_elems_rw_user(ctl, argp, false);
> case SNDRV_CTL_IOCTL_ELEM_WRITE:
> return snd_ctl_elem_write_user(ctl, argp);
> + case SNDRV_CTL_IOCTL_ELEMS_WRITE:
> + return snd_ctl_elems_rw_user(ctl, argp, true);
> case SNDRV_CTL_IOCTL_ELEM_LOCK:
> return snd_ctl_elem_lock(ctl, argp);
> case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
Thanks
Takashi Sakamoto
[cid:XOK0LK7CT9SZ@namo.co.kr]
[update?userid=satendra.t&do=bWFpbElEPTIwMTcwMjAzMDUyODQ5ZXBjbXM1cDQ4Yz
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing values of multiple controls in one go (at once)
2017-02-02 3:45 ` Takashi Sakamoto
@ 2017-02-03 7:24 ` Takashi Iwai
0 siblings, 0 replies; 5+ messages in thread
From: Takashi Iwai @ 2017-02-03 7:24 UTC (permalink / raw)
To: Takashi Sakamoto
Cc: alsa-devel, ycheon.song, linux-kernel, nishant.s4, hemanshu.s,
Satendra Singh Thakur
On Thu, 02 Feb 2017 04:45:48 +0100,
Takashi Sakamoto wrote:
>
> Hi,
>
> On Feb 2 2017 12:14, Satendra Singh Thakur wrote:
> > From: satendra singh thakur <satendra.t@samsung.com>
> >
> > -Added 2 ioctls in alsa driver's control interface
> > -Added an ioctl to read values of multiple elements at once
> > -Added an ioctl to write values of multiple elements at once
> > -In the absence of above ioctls user needs to call N ioctls to
> > read/write value of N elements which requires N context switches
> > -Proposed ioctls will allow accessing N elements' values in a single
> > context switch
> > -Above mentioned ioctl will be useful for alsa utils such as amixer
> > which reads all controls of given sound card
> >
> > Signed-off-by: Satendra Singh Thakur <satendra.t@samsung.com>
> > ---
> > include/uapi/sound/asound.h | 8 +++++
> > sound/core/control.c | 69 +++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 77 insertions(+)
>
> I'm _strongly_ interested in your two patches, because it has a
> potentiality to purge ASoC abuse of TLV feature, which was introduced
> in 2014 with a bad reviewing process.
I don't think it can be a replacement for the extended TLV usages.
The proposed API is nothing but a loop of ctl elem read/write, and I'm
not sure whether it worth to introduce the new ioctls just for that.
Takashi
^ permalink raw reply [flat|nested] 5+ messages in thread
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2017-02-02 3:14 ` [RFC] [ALSA][CONTROL] Added 2 ioctls for reading/writing values of multiple controls in one go (at once) Satendra Singh Thakur
2017-02-02 3:45 ` Takashi Sakamoto
2017-02-03 7:24 ` Takashi Iwai
2017-02-02 17:22 ` [alsa-devel] " Clemens Ladisch
2017-02-03 5:28 ` Satendra Singh Thakur
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