[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <s5hlgl7dqqa.wl-tiwai@suse.de>
Date: Fri, 22 Sep 2017 11:31:25 +0200
From: Takashi Iwai <tiwai@...e.de>
To: "Baolin Wang" <baolin.wang@...aro.org>
Cc: <perex@...ex.cz>, <alsa-devel@...a-project.org>, <arnd@...db.de>,
<arvind.yadav.cs@...il.com>, <bhumirks@...il.com>,
<deepa.kernel@...il.com>, <lgirdwood@...il.com>,
<dharageswari.r@...el.com>, <gudishax.kranthikumar@...el.com>,
<guneshwor.o.singh@...el.com>, <hardik.t.shah@...el.com>,
<jeeja.kp@...el.com>, <naveen.m@...el.com>, <vinod.koul@...el.com>,
<broonie@...nel.org>, <mingo@...nel.org>,
<dan.carpenter@...cle.com>, <o-takashi@...amocchi.jp>,
<fabf@...net.be>, <elfring@...rs.sourceforge.net>,
<linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 2/7] sound: core: Avoid using timespec for struct snd_pcm_status
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
Powered by blists - more mailing lists