Re: [PATCH 01/13] ALSA: pcm: add more sample rate definitions

[Jerome Brunet]

On Wed 11 Sep 2024 at 14:42, Takashi Iwai <tiwai@xxxxxxx> wrote:

> On Wed, 11 Sep 2024 12:58:53 +0200,
> Jaroslav Kysela wrote:
>> 
>> On 11. 09. 24 12:51, Takashi Iwai wrote:
>> > On Wed, 11 Sep 2024 12:33:01 +0200,
>> > Péter Ujfalusi wrote:
>> >> 
>> >> On 11/09/2024 12:21, Takashi Iwai wrote:
>> >>>> Wondering if this is backwards compatible with the alsa-lib definitions,
>> >>>> specifically the topology parts which did unfortunately have a list of
>> >>>> rates that will map to a different index now:
>> >>>> 
>> >>>> 
>> >>>> typedef enum _snd_pcm_rates {
>> >>>> 	SND_PCM_RATE_UNKNOWN = -1,
>> >>>> 	SND_PCM_RATE_5512 = 0,
>> >>>> 	SND_PCM_RATE_8000,
>> >>>> 	SND_PCM_RATE_11025,
>> >>>> 	SND_PCM_RATE_16000,
>> >>>> 	SND_PCM_RATE_22050,
>> >>>> 	SND_PCM_RATE_32000,
>> >>>> 	SND_PCM_RATE_44100,
>> >>>> 	SND_PCM_RATE_48000,
>> >>>> 	SND_PCM_RATE_64000,
>> >>>> 	SND_PCM_RATE_88200,
>> >>>> 	SND_PCM_RATE_96000,
>> >>>> 	SND_PCM_RATE_176400,
>> >>>> 	SND_PCM_RATE_192000,
>> >>>> 	SND_PCM_RATE_CONTINUOUS = 30,
>> >>>> 	SND_PCM_RATE_KNOT = 31,
>> >>>> 	SND_PCM_RATE_LAST = SND_PCM_RATE_KNOT,
>> >>>> } snd_pcm_rates_t;
>> >>> 
>> >>> As far as I understand correctly, those rate bits used for topology
>> >>> are independent from the bits used for PCM core, although it used to
>> >>> be the same.  Maybe better to rename (such as SND_TPLG_RATE_*) so that
>> >>> it's clearer only for topology stuff.
>> >> 
>> >> Even if we rename these in alsa-lib we will need translation from
>> >> SND_TPLG_RATE_ to SND_PCM_RATE_ in kernel likely?
>> >> 
>> >> The topology files are out there and this is an ABI...
>> >> 
>> >>> But it'd be better if anyone can double-check.
>> >> 
>> >> Since the kernel just copies the rates bitfield, any rate above 11025
>> >> will be misaligned and result broken setup.
>> > 
>> > Yep, I noticed it now, too.
>> > 
>> > Below is the fix patch, totally untested.
>> > It'd be appreciated if anyone can test it quickly.
>> > 
>> > 
>> > thanks,
>> > 
>> > Takashi
>> > 
>> > -- 8< --
>> > From: Takashi Iwai <tiwai@xxxxxxx>
>> > Subject: [PATCH] ALSA: pcm: Fix breakage of PCM rates used for topology
>> > 
>> > It turned out that the topology ABI takes the standard PCM rate bits
>> > as is, and it means that the recent change of the PCM rate bits would
>> > lead to the inconsistent rate values used for topology.
>> > 
>> > This patch reverts the original PCM rate bit definitions while adding
>> > the new rates to the extended bits instead.  This needed the change of
>> > snd_pcm_known_rates, too.  And this also required to fix the handling
>> > in snd_pcm_hw_limit_rates() that blindly assumed that the list is
>> > sorted while it became unsorted now.
>> > 
>> > Fixes: 090624b7dc83 ("ALSA: pcm: add more sample rate definitions")
>> > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
>> 
>> This looks fine. But the topology rate bits should not depend on those
>> bits. It's a bit pitty that the standard PCM ABI does not use those
>> bits for user space and we are doing this change just for topology
>> ABI.
>
> Yeah, and theoretically it's possible to fix in topology side, but
> it'll be more cumbersome.
>
> Although it's not really a part of PCM ABI, I believe we should move
> the PCM rate bit definitions to uapi, for showing that it's set in
> stone.  Something like below.
>
>
> Takashi
>
> -- 8< --
> From: Takashi Iwai <tiwai@xxxxxxx>
> Subject: [PATCH] ALSA: pcm: Move standard rate bit definitions into uapi
>
> Since the standard PCM rate bits are used for the topology ABI, it's a
> part of public ABI that must not be changed.  Move the definitions
> into uapi to indicate it more clearly.
>
> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> ---
>  include/sound/pcm.h         | 26 --------------------------
>  include/uapi/sound/asound.h | 26 ++++++++++++++++++++++++++
>  2 files changed, 26 insertions(+), 26 deletions(-)
>
> diff --git a/include/sound/pcm.h b/include/sound/pcm.h
> index 824216799070..f28f6d6ac996 100644
> --- a/include/sound/pcm.h
> +++ b/include/sound/pcm.h
> @@ -105,32 +105,6 @@ struct snd_pcm_ops {
>  
>  #define SNDRV_PCM_POS_XRUN		((snd_pcm_uframes_t)-1)
>  
> -/* If you change this don't forget to change rates[] table in pcm_native.c */
> -#define SNDRV_PCM_RATE_5512		(1U<<0)		/* 5512Hz */
> -#define SNDRV_PCM_RATE_8000		(1U<<1)		/* 8000Hz */
> -#define SNDRV_PCM_RATE_11025		(1U<<2)		/* 11025Hz */
> -#define SNDRV_PCM_RATE_16000		(1U<<3)		/* 16000Hz */
> -#define SNDRV_PCM_RATE_22050		(1U<<4)		/* 22050Hz */
> -#define SNDRV_PCM_RATE_32000		(1U<<5)		/* 32000Hz */
> -#define SNDRV_PCM_RATE_44100		(1U<<6)		/* 44100Hz */
> -#define SNDRV_PCM_RATE_48000		(1U<<7)		/* 48000Hz */
> -#define SNDRV_PCM_RATE_64000		(1U<<8)		/* 64000Hz */
> -#define SNDRV_PCM_RATE_88200		(1U<<9)		/* 88200Hz */
> -#define SNDRV_PCM_RATE_96000		(1U<<10)	/* 96000Hz */
> -#define SNDRV_PCM_RATE_176400		(1U<<11)	/* 176400Hz */
> -#define SNDRV_PCM_RATE_192000		(1U<<12)	/* 192000Hz */
> -#define SNDRV_PCM_RATE_352800		(1U<<13)	/* 352800Hz */
> -#define SNDRV_PCM_RATE_384000		(1U<<14)	/* 384000Hz */
> -#define SNDRV_PCM_RATE_705600		(1U<<15)	/* 705600Hz */
> -#define SNDRV_PCM_RATE_768000		(1U<<16)	/* 768000Hz */
> -/* extended rates */

It is cosmetic but I wonder, does the extended really start here ?

>From the table Pierre-Louis sent, I suppose that all the recently added rates could
been seen as extended too (352.8 to 768). Those did not mess with the
order though 

> -#define SNDRV_PCM_RATE_12000		(1U<<17)	/* 12000Hz */
> -#define SNDRV_PCM_RATE_24000		(1U<<18)	/* 24000Hz */
> -#define SNDRV_PCM_RATE_128000		(1U<<19)	/* 128000Hz */
> -
> -#define SNDRV_PCM_RATE_CONTINUOUS	(1U<<30)	/* continuous range */
> -#define SNDRV_PCM_RATE_KNOT		(1U<<31)	/* supports more non-continuous rates */
> -
>  #define SNDRV_PCM_RATE_8000_44100	(SNDRV_PCM_RATE_8000|SNDRV_PCM_RATE_11025|\
>  					 SNDRV_PCM_RATE_16000|SNDRV_PCM_RATE_22050|\
>  					 SNDRV_PCM_RATE_32000|SNDRV_PCM_RATE_44100)
> diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
> index 4cd513215bcd..715ceb3eac7c 100644
> --- a/include/uapi/sound/asound.h
> +++ b/include/uapi/sound/asound.h
> @@ -272,6 +272,32 @@ typedef int __bitwise snd_pcm_subformat_t;
>  #define	SNDRV_PCM_SUBFORMAT_MSBITS_24	((__force snd_pcm_subformat_t) 3)
>  #define	SNDRV_PCM_SUBFORMAT_LAST	SNDRV_PCM_SUBFORMAT_MSBITS_24
>  
> +/* Standard rate bits */
> +#define SNDRV_PCM_RATE_5512		(1U<<0)		/* 5512Hz */
> +#define SNDRV_PCM_RATE_8000		(1U<<1)		/* 8000Hz */
> +#define SNDRV_PCM_RATE_11025		(1U<<2)		/* 11025Hz */
> +#define SNDRV_PCM_RATE_16000		(1U<<3)		/* 16000Hz */
> +#define SNDRV_PCM_RATE_22050		(1U<<4)		/* 22050Hz */
> +#define SNDRV_PCM_RATE_32000		(1U<<5)		/* 32000Hz */
> +#define SNDRV_PCM_RATE_44100		(1U<<6)		/* 44100Hz */
> +#define SNDRV_PCM_RATE_48000		(1U<<7)		/* 48000Hz */
> +#define SNDRV_PCM_RATE_64000		(1U<<8)		/* 64000Hz */
> +#define SNDRV_PCM_RATE_88200		(1U<<9)		/* 88200Hz */
> +#define SNDRV_PCM_RATE_96000		(1U<<10)	/* 96000Hz */
> +#define SNDRV_PCM_RATE_176400		(1U<<11)	/* 176400Hz */
> +#define SNDRV_PCM_RATE_192000		(1U<<12)	/* 192000Hz */
> +#define SNDRV_PCM_RATE_352800		(1U<<13)	/* 352800Hz */
> +#define SNDRV_PCM_RATE_384000		(1U<<14)	/* 384000Hz */
> +#define SNDRV_PCM_RATE_705600		(1U<<15)	/* 705600Hz */
> +#define SNDRV_PCM_RATE_768000		(1U<<16)	/* 768000Hz */
> +/* extended rates */
> +#define SNDRV_PCM_RATE_12000		(1U<<17)	/* 12000Hz */
> +#define SNDRV_PCM_RATE_24000		(1U<<18)	/* 24000Hz */
> +#define SNDRV_PCM_RATE_128000		(1U<<19)	/* 128000Hz */
> +
> +#define SNDRV_PCM_RATE_CONTINUOUS	(1U<<30)	/* continuous range */
> +#define SNDRV_PCM_RATE_KNOT		(1U<<31)	/* supports more non-continuous rates */
> +
>  #define SNDRV_PCM_INFO_MMAP		0x00000001	/* hardware supports mmap */
>  #define SNDRV_PCM_INFO_MMAP_VALID	0x00000002	/* period data are valid during transfer */
>  #define SNDRV_PCM_INFO_DOUBLE		0x00000004	/* Double buffering needed for PCM start/stop */

-- 
Jerome