From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takashi Iwai <tiwai@suse.de>
Subject: Re: [PATCH 6/7] ALSA: hda/tegra: fix kernel panic
Date: Tue, 22 Jan 2019 07:24:57 +0100
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To: Sameer Pujar <spujar@nvidia.com>
Cc: alsa-devel@alsa-project.org, broonie@kernel.org
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On Tue, 22 Jan 2019 04:41:16 +0100,
Sameer Pujar wrote:
> 
> 
> On 1/22/2019 2:58 AM, Takashi Iwai wrote:
> > On Mon, 21 Jan 2019 18:41:36 +0100,
> > Sameer Pujar wrote:
> >> Kernel panic is seen during device boot. It appears that before the
> >> probe completes, runtime callbacks happen and the device setup is not
> >> done yet. This could be initiated from framework through exposed
> >> callbacks. This issue can be fixed by having a flag to indicate
> >> completion of device probe. Hence 'probed' flag is introduced to notify
> >> completion of probe and runtime callbacks can check this flag before
> >> doing any device access.
> > Such a fix should be rather folded into the previous, especially if
> > you know it's already broken :)
> Ok, I will meld this with previous commit.
> >
> > And, IMO, it's better to put such a check into runtime_idle callback
> > instead of doing in each (runtime_)suspend/resume callback.
> Check in runtime_idle would take care of suspend path. But how the check in
> runtime_resume can be avoided? Kernel panic happened during
> runtime_resume().

Hm, right, we need the check in both places, since runtime PM is
called from the system PM, too.

BTW, I guess we can check chip->running instead of adding a new flag.


thanks,

Takashi