From: Takashi Iwai <tiwai@suse.de>
To: "Yang, Libin" <libin.yang@intel.com>
Cc: "intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>,
"Vetter, Daniel" <daniel.vetter@intel.com>,
"libin.yang@linux.intel.com" <libin.yang@linux.intel.com>
Subject: Re: [PATCH] drm/i915: add audio_ptr pointer check
Date: Wed, 02 Mar 2016 09:56:58 +0100 [thread overview]
Message-ID: <s5hk2lltfz9.wl-tiwai@suse.de> (raw)
In-Reply-To: <96A12704CE18D347B625EE2D4A099D190467E37F@SHSMSX103.ccr.corp.intel.com>
On Wed, 02 Mar 2016 08:59:23 +0100,
Yang, Libin wrote:
>
> Hi Takashi,
>
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai@suse.de]
> > Sent: Wednesday, March 02, 2016 3:44 PM
> > To: libin.yang@linux.intel.com
> > Cc: intel-gfx@lists.freedesktop.org; conselvan2@gmail.com;
> > jani.nikula@linux.intel.com; ville.syrjala@linux.intel.com; Vetter, Daniel;
> > tiwai@suse.de; Yang, Libin
> > Subject: Re: [PATCH] drm/i915: add audio_ptr pointer check
> >
> > On Wed, 02 Mar 2016 03:24:31 +0100,
> > libin.yang@linux.intel.com wrote:
> > >
> > > From: Libin Yang <libin.yang@linux.intel.com>
> > >
> > > check to make sure audio_ptr is not NULL before
> > > using it.
> >
> > I don't think non-NULL is mandatory. If any invalid access is seen,
> > it should be fixed rather in the audio side.
>
> When I enable MST with other patches (not submitted so far),
> I found system may be random hang when boot up.
>
> After apply this patch and another patch (I sent the patch in
> ALSA Mail list: ALSA: hda - hdmi defer to register acomp eld notifier),
> the hang issue is fixed.
>
> I make the patch because in sound driver side, setting audio_ptr and
> audio_ops is not in the lock. I'm wondering that the compiler or CPU
> may optimize and change the setting order (the gfx code and alsa code
> may run parallelly?).
There are several ways to deal with such a thing. An easy one would
be the memory barrier.
Takashi
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next prev parent reply other threads:[~2016-03-02 8:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 2:24 [PATCH] drm/i915: add audio_ptr pointer check libin.yang
2016-03-02 7:44 ` Takashi Iwai
2016-03-02 7:59 ` Yang, Libin
2016-03-02 8:56 ` Takashi Iwai [this message]
2016-03-03 3:01 ` Yang, Libin
2016-03-02 8:00 ` Jani Nikula
2016-03-02 8:31 ` ✗ Fi.CI.BAT: warning for " Patchwork
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