tools include UAPI: Sync sound/asound.h copy with the kernel sources

Picking the changes from:

  55b71f6c29f2a78a ("ALSA: uapi: use C90 comment style instead of C99 style")
  fb6723daf89083a0 ("ALSA: pcm: comment about relation between msbits hw parameter and [S|U]32 formats")
  b456abe63f60ad93 ("ALSA: pcm: introduce INFO_NO_REWINDS flag")
  5aec579e08e4f2be ("ALSA: uapi: Fix a C++ style comment in asound.h")

Which entails no changes in the tooling side as it doesn't introduce new
SNDRV_PCM_IOCTL_ ioctls.

To silence this perf tools build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/sound/asound.h' differs from latest version at 'include/uapi/sound/asound.h'
  diff -u tools/include/uapi/sound/asound.h include/uapi/sound/asound.h

Cc: Mark Brown <broonie@kernel.org>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/all/YflN0j09T+6ODHIh@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/include/uapi/sound/asound.h b/tools/include/uapi/sound/asound.h
index 5fbb79e..ef0cafe 100644 (file)
--- a/tools/include/uapi/sound/asound.h
+++ b/tools/include/uapi/sound/asound.h
@@ -202,6 +202,11 @@ typedef int __bitwise snd_pcm_format_t;
 #define        SNDRV_PCM_FORMAT_S24_BE ((__force snd_pcm_format_t) 7) /* low three bytes */
 #define        SNDRV_PCM_FORMAT_U24_LE ((__force snd_pcm_format_t) 8) /* low three bytes */
 #define        SNDRV_PCM_FORMAT_U24_BE ((__force snd_pcm_format_t) 9) /* low three bytes */
+/*
+ * For S32/U32 formats, 'msbits' hardware parameter is often used to deliver information about the
+ * available bit count in most significant bit. It's for the case of so-called 'left-justified' or
+ * `right-padding` sample which has less width than 32 bit.
+ */
 #define        SNDRV_PCM_FORMAT_S32_LE ((__force snd_pcm_format_t) 10)
 #define        SNDRV_PCM_FORMAT_S32_BE ((__force snd_pcm_format_t) 11)
 #define        SNDRV_PCM_FORMAT_U32_LE ((__force snd_pcm_format_t) 12)
@@ -300,7 +305,7 @@ typedef int __bitwise snd_pcm_subformat_t;
 #define SNDRV_PCM_INFO_HAS_LINK_ESTIMATED_ATIME    0x04000000  /* report estimated link audio time */
 #define SNDRV_PCM_INFO_HAS_LINK_SYNCHRONIZED_ATIME 0x08000000  /* report synchronized audio/system time */
 #define SNDRV_PCM_INFO_EXPLICIT_SYNC   0x10000000      /* needs explicit sync of pointers and data */
-
+#define SNDRV_PCM_INFO_NO_REWINDS      0x20000000      /* hardware can only support monotonic changes of appl_ptr */
 #define SNDRV_PCM_INFO_DRAIN_TRIGGER   0x40000000              /* internal kernel flag - trigger in drain */
 #define SNDRV_PCM_INFO_FIFO_IN_FRAMES  0x80000000      /* internal kernel flag - FIFO size is in frames */