Re: [RFC PATCH 2/7] sound: core: Avoid using timespec for struct snd_pcm_status

[Takashi Iwai <tiwai@suse.de>]

On Thu, 21 Sep 2017 08:18:04 +0200,
Baolin Wang wrote:
> 
> The struct snd_pcm_status will use 'timespec' type variables to record
> timestamp, which is not year 2038 safe on 32bits system.
> 
> Userspace will use SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT
> as commands to issue ioctl() to fill the 'snd_pcm_status' structure in
> userspace. The command number is always defined through _IOR/_IOW/IORW,
> so when userspace changes the definition of 'struct timespec' to use
> 64-bit types, the command number also changes.
> 
> Thus in the kernel, we now need to define two versions of each such ioctl
> and corresponding ioctl commands to handle 32bit time_t and 64bit time_t
> in native mode:
> struct snd_pcm_status32 {
> 	......
> 	struct { s32 tv_sec; s32 tv_nsec; } trigger_tstamp;
> 	struct { s32 tv_sec; s32 tv_nsec; } tstamp;
> 	......
> }
> 
> struct snd_pcm_status64 {
> 	......
> 	struct { s64 tv_sec; s64 tv_nsec; } trigger_tstamp;
> 	struct { s64 tv_sec; s64 tv_nsec; } tstamp;
> 	......
> }

I'm confused.  It's different from timespec64?  So 32bit user-space
would need to use a new own-type timespec instead of the standard
timespec that is compliant with y2038?


thanks,

Takashi