On Tue, Apr 24, 2018 at 2:06 PM, Baolin Wang <baolin.wang@xxxxxxxxxx> 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
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