Mixer chanel naming

Mixer chanel naming

[Kasparek Tomas]

Hi,

I've just started writing driver for Compaq iPAQ and I'm feel realy dizzy
from setting the mixer. Here is part of code:

...
static snd_kcontrol_new_t snd_h3600_controls[] = {
H3600_SINGLE("Master Playback Switch", H3600_MASTER, 15, 1, 1),
H3600_DOUBLE("Master Playback Volume", H3600_MASTER, 8, 0, 31, 1),
...

First argument is used for "name" item of snd_kcontrol_new_t structure.
It look like the name is significant when configuring this new control.

(e.g. without "playback", alsamixer shows two devices for one entry)

Where should I find information of possible names and mainly their
meaning? How functionality of such defined control depends on this name?

Thanks

--

	Tomas Kasparek (sioux, xkaspa06)
 	 Tomas.Kasparek@[seznam.cz,volny.cz]
	 Linux@dcse.fee.vutbr.cz
	student UIVT FEI VUT Brno


_______________________________________________
Alsa-devel mailing list
Alsa-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/alsa-devel

Re: Mixer chanel naming

[Takashi Iwai]

Hi,

At Fri, 8 Mar 2002 14:01:30 +0100 (CET),
Kasparek Tomas wrote:
> 
> Hi,
> 
> I've just started writing driver for Compaq iPAQ and I'm feel realy dizzy
> from setting the mixer. Here is part of code:
> 
> ...
> static snd_kcontrol_new_t snd_h3600_controls[] = {
> H3600_SINGLE("Master Playback Switch", H3600_MASTER, 15, 1, 1),
> H3600_DOUBLE("Master Playback Volume", H3600_MASTER, 8, 0, 31, 1),
> ...
> 
> First argument is used for "name" item of snd_kcontrol_new_t structure.
> It look like the name is significant when configuring this new control.
> 
> (e.g. without "playback", alsamixer shows two devices for one entry)
> 
> Where should I find information of possible names and mainly their
> meaning? How functionality of such defined control depends on this name?

check out alsa-driver/doc/ControlNames.


Takashi

_______________________________________________
Alsa-devel mailing list
Alsa-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/alsa-devel

Re: Mixer chanel naming

[Jaroslav Kysela]

On Fri, 8 Mar 2002, Kasparek Tomas wrote:

> Hi,
> 
> I've just started writing driver for Compaq iPAQ and I'm feel realy dizzy
> from setting the mixer. Here is part of code:
> 
> ...
> static snd_kcontrol_new_t snd_h3600_controls[] = {
> H3600_SINGLE("Master Playback Switch", H3600_MASTER, 15, 1, 1),
> H3600_DOUBLE("Master Playback Volume", H3600_MASTER, 8, 0, 31, 1),
> ...
> 
> First argument is used for "name" item of snd_kcontrol_new_t structure.
> It look like the name is significant when configuring this new control.
> 
> (e.g. without "playback", alsamixer shows two devices for one entry)
> 
> Where should I find information of possible names and mainly their
> meaning? How functionality of such defined control depends on this name?

The recommended names for controls are defined in 
the alsa-driver/doc/ControlNames document (should be probably moved to 
alsa-kernel/Documentation).

						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project  http://www.alsa-project.org
SuSE Linux    http://www.suse.com


_______________________________________________
Alsa-devel mailing list
Alsa-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/alsa-devel

PATCH: snd_pcm_playback_silence

[Sander van Leeuwen]

Hi,

I'm currently porting ALSA to OS/2 and have encountered a bug in
snd_pcm_playback_silence (core\pcm_lib.c)
While playing an 8 bits stereo 44.1khz wave file the system
would trap when stopping the stream. The cause was heap
corruption caused by this function. There is no check to
see if the offset + amount of frames to silence is larger
than the buffer size.
The patch below fixes this.

Sander



--- E:\Development\ALSA.Linux\alsa-kernel\core\pcm_lib.c	Wed Apr 10 21:55:18 2002
+++ E:\Development\ALSA.OS2\GPL\alsa\core\pcm_lib.c	Thu Apr 11 17:01:38 2002
@@ -60,6 +56,12 @@
 	ofs = runtime->silenced_start % runtime->buffer_size + runtime->silenced_size;
 	if (ofs >= runtime->buffer_size)
 		ofs -= runtime->buffer_size;
+#ifdef TARGET_OS2
+        if (ofs + frames > runtime->buffer_size) {
+                frames = runtime->buffer_size - ofs;
+        }
+#endif
 	if (runtime->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED ||
 	    runtime->access == SNDRV_PCM_ACCESS_MMAP_INTERLEAVED) {
 		if (substream->ops->silence) {

Re: PATCH: snd_pcm_playback_silence

[Jaroslav Kysela]

On Thu, 11 Apr 2002, Sander van Leeuwen wrote:

> Hi,
> 
> I'm currently porting ALSA to OS/2 and have encountered a bug in
> snd_pcm_playback_silence (core\pcm_lib.c)
> While playing an 8 bits stereo 44.1khz wave file the system
> would trap when stopping the stream. The cause was heap
> corruption caused by this function. There is no check to
> see if the offset + amount of frames to silence is larger
> than the buffer size.
> The patch below fixes this.
> 
> Sander
> 
> 
> 
> --- E:\Development\ALSA.Linux\alsa-kernel\core\pcm_lib.c	Wed Apr 10 21:55:18 2002
> +++ E:\Development\ALSA.OS2\GPL\alsa\core\pcm_lib.c	Thu Apr 11 17:01:38 2002
> @@ -60,6 +56,12 @@
>  	ofs = runtime->silenced_start % runtime->buffer_size + runtime->silenced_size;
>  	if (ofs >= runtime->buffer_size)
>  		ofs -= runtime->buffer_size;
> +#ifdef TARGET_OS2
> +        if (ofs + frames > runtime->buffer_size) {
> +                frames = runtime->buffer_size - ofs;
> +        }
> +#endif
>  	if (runtime->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED ||
>  	    runtime->access == SNDRV_PCM_ACCESS_MMAP_INTERLEAVED) {
>  		if (substream->ops->silence) {

Above patch is not perfect, but thank you for pointing to this problem. 
I've applied this fix to CVS:

Index: pcm_lib.c
===================================================================
RCS file: /cvsroot/alsa/alsa-kernel/core/pcm_lib.c,v
retrieving revision 1.9
diff -u -r1.9 pcm_lib.c
--- pcm_lib.c	9 Apr 2002 06:53:35 -0000	1.9
+++ pcm_lib.c	12 Apr 2002 07:04:47 -0000
@@ -34,7 +34,7 @@
 void snd_pcm_playback_silence(snd_pcm_substream_t *substream)
 {
 	snd_pcm_runtime_t *runtime = substream->runtime;
-	snd_pcm_uframes_t frames, ofs;
+	snd_pcm_uframes_t frames, ofs, transfer;
 	snd_pcm_sframes_t noise_dist;
 	if (runtime->silenced_start != runtime->control->appl_ptr) {
 		snd_pcm_sframes_t n = runtime->control->appl_ptr - runtime->silenced_start;
@@ -60,32 +60,36 @@
 	ofs = runtime->silenced_start % runtime->buffer_size + runtime->silenced_size;
 	if (ofs >= runtime->buffer_size)
 		ofs -= runtime->buffer_size;
-	if (runtime->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED ||
-	    runtime->access == SNDRV_PCM_ACCESS_MMAP_INTERLEAVED) {
-		if (substream->ops->silence) {
-			int err;
-			err = substream->ops->silence(substream, -1, ofs, frames);
-			snd_assert(err >= 0, );
-		} else {
-			char *hwbuf = runtime->dma_area + frames_to_bytes(runtime, ofs);
-			snd_pcm_format_set_silence(runtime->format, hwbuf, frames * runtime->channels);
-		}
-	} else {
-		unsigned int c;
-		unsigned int channels = runtime->channels;
-		if (substream->ops->silence) {
-			for (c = 0; c < channels; ++c) {
+	while (frames > 0) {
+		transfer = ofs + frames > runtime->buffer_size ? runtime->buffer_size - ofs : frames;
+		if (runtime->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED ||
+		    runtime->access == SNDRV_PCM_ACCESS_MMAP_INTERLEAVED) {
+			if (substream->ops->silence) {
 				int err;
-				err = substream->ops->silence(substream, c, ofs, frames);
+				err = substream->ops->silence(substream, -1, ofs, transfer);
 				snd_assert(err >= 0, );
+			} else {
+				char *hwbuf = runtime->dma_area + frames_to_bytes(runtime, ofs);
+				snd_pcm_format_set_silence(runtime->format, hwbuf, transfer * runtime->channels);
 			}
 		} else {
-			size_t dma_csize = runtime->dma_bytes / channels;
-			for (c = 0; c < channels; ++c) {
-				char *hwbuf = runtime->dma_area + (c * dma_csize) + samples_to_bytes(runtime, ofs);
-				snd_pcm_format_set_silence(runtime->format, hwbuf, frames);
+			unsigned int c;
+			unsigned int channels = runtime->channels;
+			if (substream->ops->silence) {
+				for (c = 0; c < channels; ++c) {
+					int err;
+					err = substream->ops->silence(substream, c, ofs, transfer);
+					snd_assert(err >= 0, );
+				}
+			} else {
+				size_t dma_csize = runtime->dma_bytes / channels;
+				for (c = 0; c < channels; ++c) {
+					char *hwbuf = runtime->dma_area + (c * dma_csize) + samples_to_bytes(runtime, ofs);
+					snd_pcm_format_set_silence(runtime->format, hwbuf, transfer);
+				}
 			}
 		}
+		frames -= transfer;
 	}
 	runtime->silenced_size += frames;
 }


						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project  http://www.alsa-project.org
SuSE Linux    http://www.suse.com