On Tue, Apr 24, 2018 at 2:06 PM, Baolin Wang baolin.wang@linaro.org wrote:
-struct snd_pcm_mmap_status { +/*
- For mmap operations, we need the 64-bit layout, both for compat mode,
- and for y2038 compatibility. For 64-bit applications, the two definitions
- are identical, so we keep the traditional version.
- */
+#ifdef __SND_STRUCT_TIME64 +#define __snd_pcm_mmap_status64 snd_pcm_mmap_status +#define __snd_pcm_mmap_control64 snd_pcm_mmap_control +#define __snd_pcm_sync_ptr64 snd_pcm_sync_ptr +#else +#define __snd_pcm_mmap_status snd_pcm_mmap_status +#define __snd_pcm_mmap_control snd_pcm_mmap_control +#define __snd_pcm_sync_ptr snd_pcm_sync_ptr +#endif
+struct __snd_pcm_mmap_status { snd_pcm_state_t state; /* RO: state - SNDRV_PCM_STATE_XXXX */ int pad1; /* Needed for 64 bit alignment */ snd_pcm_uframes_t hw_ptr; /* RO: hw ptr (0...boundary-1) */
One more thing here: this definition is slightly suboptimal because in an alsa-lib that gets built with 64-bit time_t, we end up with an unusable __snd_pcm_mmap_status structure (__snd_pcm_mmap_status64 works fine, and that would be the normal thing to use). Just in case we want to be able to build an alsa-lib that is capable of running both on new kernels with 64-bit time_t interfaces exposed to applications and also on old kernels that don't have the new ioctls, we probably want another fixup merged in:
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index 18fbdcb2c7b6..638c717d3eb9 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -496,19 +496,30 @@ struct snd_pcm_status { #define __snd_pcm_mmap_status64 snd_pcm_mmap_status #define __snd_pcm_mmap_control64 snd_pcm_mmap_control #define __snd_pcm_sync_ptr64 snd_pcm_sync_ptr +#define __snd_timespec64 timespec +struct __snd_timespec { + __s32 tv_sec; + __s32 tv_nsec; +}; #else #define __snd_pcm_mmap_status snd_pcm_mmap_status #define __snd_pcm_mmap_control snd_pcm_mmap_control #define __snd_pcm_sync_ptr snd_pcm_sync_ptr +#define __snd_timespec timespec +struct __snd_timespec64 { + __s64 tv_sec; + __s64 tv_nsec; +}; + #endif
struct __snd_pcm_mmap_status { snd_pcm_state_t state; /* RO: state - SNDRV_PCM_STATE_XXXX */ int pad1; /* Needed for 64 bit alignment */ snd_pcm_uframes_t hw_ptr; /* RO: hw ptr (0...boundary-1) */ - struct timespec tstamp; /* Timestamp */ + struct __snd_timespec tstamp; /* Timestamp */ snd_pcm_state_t suspended_state; /* RO: suspended stream state */ - struct timespec audio_tstamp; /* from sample counter or wall clock */ + struct __snd_timespec audio_tstamp; /* from sample counter or wall clock */ };
struct __snd_pcm_mmap_control { @@ -532,11 +543,6 @@ struct __snd_pcm_sync_ptr { } c; };
-struct __snd_timespec64 { - __s64 tv_sec; - __s64 tv_nsec; -}; - #if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN) typedef char __pad_before_uframe[sizeof(__u64) - sizeof(snd_pcm_uframes_t)]; typedef char __pad_after_uframe[0];
With this change, alsa-lib can either access whichever structure matches the glibc 'timespec' definition, or it can ask for __struct __snd_pcm_mmap_status and struct __snd_pcm_mmap_status64 explicitly, regardless of the time_t definition.
Arnd