Re: [Intel-gfx] [PATCH] ALSA: hda: Release display power reference during shutdown/reboot

From: Takashi Iwai <tiwai@suse.de>
To: Imre Deak <imre.deak@intel.com>
Cc: Thomas Voegtle <tv@lio96.de>, intel-gfx@lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH] ALSA: hda: Release display power reference during shutdown/reboot
Date: Tue, 22 Jun 2021 16:18:14 +0200	[thread overview]
Message-ID: <s5h5yy6q8yh.wl-tiwai@suse.de> (raw)
In-Reply-To: <20210621174415.1721198-1-imre.deak@intel.com>

On Mon, 21 Jun 2021 19:44:15 +0200,
Imre Deak wrote:
> 
> Make sure the HDA driver's display power reference is released during
> shutdown/reboot.
> 
> During the shutdown/reboot sequence the pci device core calls the
> pm_runtime_resume handler for all devices before calling the driver's
> shutdown callback and so the HDA driver's runtime resume callback will
> acquire a display power reference (on HSW/BDW). This triggers a power
> reference held WARN on HSW/BDW in the i915 driver's subsequent shutdown
> handler, which expects all display power references to be released by
> that time.
> 
> Since the HDA controller is stopped in the shutdown handler in any case,
> let's follow here the same sequence as the one during runtime suspend.
> This will also reset the HDA link and drop the display power reference,
> getting rid of the above WARN.

As kbuild bot suggested, __azx_runtime_suspend() is defined only with
CONFIG_PM.  We need either moving the function out of ifdef CONFIG_PM
block, or having CONFIG_PM conditional call there.

I myself have no much preference,  but maybe the latter can be easier
to be cherry-picked to stable kernels.

thanks,

Takashi
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