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

[Takashi Iwai <tiwai@suse.de>]

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 */
-- 
2.43.0