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

["Amadeusz Sławiński" <amadeuszx.slawinski@linux.intel.com>]

On 9/11/2024 2:42 PM, Takashi Iwai 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@suse.de>
>>> 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@suse.de>
>>
>> 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@suse.de>
> 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@suse.de>
> ---
>   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 */
> -#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 */

I will just note that alternatively we could bump topology ABI (wouldn't 
be first time) and provide mapping in soc-topology.c for current one.

For ABI+1 we could remove the field from problematic topology struct to 
not make SNDRV_PCM_RATE_* part of UAPI and provide some other way to 
pass expected rates.