TLV question - ranges not in volume order

TLV question - ranges not in volume order

[David Henningsson]

Hi,

I recently came across a strange ASoC volume control. In this case, the 
values are not in volume order, i e, the control is declared something 
like below. I believe the numbers correctly match the hardware.

However alsamixer seems not to handle this "reordering" correctly. My 
question is if this is something that should be fixed in alsamixer (or 
possibly alsa-lib?), or does one need to write some kind of mapping 
table in the kernel, just to make something come in volume order to 
userspace?

Any TLV documentation on what TLVs are valid and invalid is also welcome :-)

static const unsigned int tlv[] = {
         TLV_DB_RANGE_HEAD(8),
         0, 0, TLV_DB_SCALE_ITEM(-100, 0, 1),
         1, 1, TLV_DB_SCALE_ITEM(400, 0, 0),
         2, 2, TLV_DB_SCALE_ITEM(200, 0, 0),
         3, 3, TLV_DB_SCALE_ITEM(1000, 0, 0),
         4, 4, TLV_DB_SCALE_ITEM(0, 0, 0),
         5, 5, TLV_DB_SCALE_ITEM(800, 0, 0),
         6, 6, TLV_DB_SCALE_ITEM(600, 0, 0),
         7, 7, TLV_DB_SCALE_ITEM(1200, 0, 0),
};

-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic

Re: TLV question - ranges not in volume order

[Clemens Ladisch]

David Henningsson wrote:
> I recently came across a strange ASoC volume control. In this case,
> the values are not in volume order, i e, the control is declared
> something like below.
>
> However alsamixer seems not to handle this "reordering" correctly. My
> question is if this is something that should be fixed in alsamixer (or
> possibly alsa-lib?), or does one need to write some kind of mapping
> table in the kernel, just to make something come in volume order to
> userspace?

Items in a DB_RANGE container must be ordered by their values *and* by
their dB values.  This implies that larger values must correspond with
larger dB values, whis is also required for all other mixer controls.

If the register values are unordered, the driver must reorder them.

> static const unsigned int tlv[] = {
>         TLV_DB_RANGE_HEAD(8),

This should be rewritten as:

static const DECLARE_TLV_DB_RANGE(tlv,
	0, 0, TLV_DB_SCALE_ITEM(-100, 0, 1),
	...
);


Regards,
Clemens

Re: TLV question - ranges not in volume order

[Takashi Iwai]

At Wed, 08 May 2013 14:09:31 +0200,
Clemens Ladisch wrote:
> 
> David Henningsson wrote:
> > I recently came across a strange ASoC volume control. In this case,
> > the values are not in volume order, i e, the control is declared
> > something like below.
> >
> > However alsamixer seems not to handle this "reordering" correctly. My
> > question is if this is something that should be fixed in alsamixer (or
> > possibly alsa-lib?), or does one need to write some kind of mapping
> > table in the kernel, just to make something come in volume order to
> > userspace?
> 
> Items in a DB_RANGE container must be ordered by their values *and* by
> their dB values.  This implies that larger values must correspond with
> larger dB values, whis is also required for all other mixer controls.
> 
> If the register values are unordered, the driver must reorder them.

Yep.  Although there is no explicit definition, it's an implicit rule,
as we have never implemented the parser code to allow the disorder.

We should add a text mentioning that somewhere.  A patch is welcome ;)


thanks,

Takashi

Re: TLV question - ranges not in volume order

[David Henningsson]

[-- Attachment #1: Type: text/plain, Size: 1261 bytes --]

On 05/08/2013 02:14 PM, Takashi Iwai wrote:
> At Wed, 08 May 2013 14:09:31 +0200,
> Clemens Ladisch wrote:
>>
>> David Henningsson wrote:
>>> I recently came across a strange ASoC volume control. In this case,
>>> the values are not in volume order, i e, the control is declared
>>> something like below.
>>>
>>> However alsamixer seems not to handle this "reordering" correctly. My
>>> question is if this is something that should be fixed in alsamixer (or
>>> possibly alsa-lib?), or does one need to write some kind of mapping
>>> table in the kernel, just to make something come in volume order to
>>> userspace?
>>
>> Items in a DB_RANGE container must be ordered by their values *and* by
>> their dB values.  This implies that larger values must correspond with
>> larger dB values, whis is also required for all other mixer controls.
>>
>> If the register values are unordered, the driver must reorder them.
>
> Yep.  Although there is no explicit definition, it's an implicit rule,
> as we have never implemented the parser code to allow the disorder.
>
> We should add a text mentioning that somewhere.  A patch is welcome ;)

Like this? (Feel free to apply if you think it's good)



-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic

[-- Attachment #2: 0001-ALSA-Add-comment-for-control-TLV-API.patch --]
[-- Type: text/x-patch, Size: 1150 bytes --]

>From 19778a06ef5bd995ba1e800dc14bbe7ff27dcb97 Mon Sep 17 00:00:00 2001
From: David Henningsson <david.henningsson@canonical.com>
Date: Wed, 8 May 2013 15:28:49 +0200
Subject: [PATCH] ALSA: Add comment for control TLV API

Userspace is not meant to have to handle all strange dB ranges,
so add a specification comment.

Signed-off-by: David Henningsson <david.henningsson@canonical.com>
---
 include/sound/tlv.h |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/sound/tlv.h b/include/sound/tlv.h
index 28c65e1..84fc31a 100644
--- a/include/sound/tlv.h
+++ b/include/sound/tlv.h
@@ -74,7 +74,10 @@
 #define DECLARE_TLV_DB_LINEAR(name, min_dB, max_dB)	\
 	unsigned int name[] = { TLV_DB_LINEAR_ITEM(min_dB, max_dB) }
 
-/* dB range container */
+/* dB range container. Items in dB range container must be ordered
+by their values and by their dB values. This implies that larger values
+must correspond with larger dB values (which is also required for all
+other mixer controls). */
 /* Each item is: <min> <max> <TLV> */
 #define TLV_DB_RANGE_ITEM(...) \
 	TLV_ITEM(SNDRV_CTL_TLVT_DB_RANGE, __VA_ARGS__)
-- 
1.7.9.5


[-- Attachment #3: Type: text/plain, Size: 0 bytes --]

Re: TLV question - ranges not in volume order

[Takashi Iwai]

At Wed, 08 May 2013 15:33:11 +0200,
David Henningsson wrote:
> 
> [1  <text/plain; ISO-8859-1 (7bit)>]
> On 05/08/2013 02:14 PM, Takashi Iwai wrote:
> > At Wed, 08 May 2013 14:09:31 +0200,
> > Clemens Ladisch wrote:
> >>
> >> David Henningsson wrote:
> >>> I recently came across a strange ASoC volume control. In this case,
> >>> the values are not in volume order, i e, the control is declared
> >>> something like below.
> >>>
> >>> However alsamixer seems not to handle this "reordering" correctly. My
> >>> question is if this is something that should be fixed in alsamixer (or
> >>> possibly alsa-lib?), or does one need to write some kind of mapping
> >>> table in the kernel, just to make something come in volume order to
> >>> userspace?
> >>
> >> Items in a DB_RANGE container must be ordered by their values *and* by
> >> their dB values.  This implies that larger values must correspond with
> >> larger dB values, whis is also required for all other mixer controls.
> >>
> >> If the register values are unordered, the driver must reorder them.
> >
> > Yep.  Although there is no explicit definition, it's an implicit rule,
> > as we have never implemented the parser code to allow the disorder.
> >
> > We should add a text mentioning that somewhere.  A patch is welcome ;)
> 
> Like this? (Feel free to apply if you think it's good)

Thanks, I applied it with slight modification (align the comment
lines).


Takashi

> 
> 
> 
> -- 
> David Henningsson, Canonical Ltd.
> https://launchpad.net/~diwic
> [2 0001-ALSA-Add-comment-for-control-TLV-API.patch <text/x-patch (7bit)>]
> >From 19778a06ef5bd995ba1e800dc14bbe7ff27dcb97 Mon Sep 17 00:00:00 2001
> From: David Henningsson <david.henningsson@canonical.com>
> Date: Wed, 8 May 2013 15:28:49 +0200
> Subject: [PATCH] ALSA: Add comment for control TLV API
> 
> Userspace is not meant to have to handle all strange dB ranges,
> so add a specification comment.
> 
> Signed-off-by: David Henningsson <david.henningsson@canonical.com>
> ---
>  include/sound/tlv.h |    5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/include/sound/tlv.h b/include/sound/tlv.h
> index 28c65e1..84fc31a 100644
> --- a/include/sound/tlv.h
> +++ b/include/sound/tlv.h
> @@ -74,7 +74,10 @@
>  #define DECLARE_TLV_DB_LINEAR(name, min_dB, max_dB)	\
>  	unsigned int name[] = { TLV_DB_LINEAR_ITEM(min_dB, max_dB) }
>  
> -/* dB range container */
> +/* dB range container. Items in dB range container must be ordered
> +by their values and by their dB values. This implies that larger values
> +must correspond with larger dB values (which is also required for all
> +other mixer controls). */
>  /* Each item is: <min> <max> <TLV> */
>  #define TLV_DB_RANGE_ITEM(...) \
>  	TLV_ITEM(SNDRV_CTL_TLVT_DB_RANGE, __VA_ARGS__)
> -- 
> 1.7.9.5
> 

Re: TLV question - ranges not in volume order

[Mark Brown]

[-- Attachment #1.1: Type: text/plain, Size: 315 bytes --]

On Wed, May 08, 2013 at 01:21:41PM +0200, David Henningsson wrote:

> I recently came across a strange ASoC volume control. In this case,
> the values are not in volume order, i e, the control is declared
> something like below. I believe the numbers correctly match the
> hardware.

Oh, joy.  What driver is this?

[-- Attachment #1.2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]

[-- Attachment #2: Type: text/plain, Size: 0 bytes --]

Re: TLV question - ranges not in volume order

[David Henningsson]

On 05/09/2013 12:12 PM, Mark Brown wrote:
> On Wed, May 08, 2013 at 01:21:41PM +0200, David Henningsson wrote:
>
>> I recently came across a strange ASoC volume control. In this case,
>> the values are not in volume order, i e, the control is declared
>> something like below. I believe the numbers correctly match the
>> hardware.
>
> Oh, joy.  What driver is this?

I think it's not in the mainline kernel at this point.



-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic