From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Anshuman Gupta <anshuman.gupta@intel.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>, Jaroslav Kysela <perex@perex.cz>,
Takashi Iwai <tiwai@suse.com>,
"moderated list:SOUND - SOC LAYER / DYNAMIC AUDIO POWER
MANAGEM..." <alsa-devel@alsa-project.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux PM <linux-pm@vger.kernel.org>
Subject: Re: [PATCH] [sound] hdac-codec runtime suspended at PM:Suspend.
Date: Mon, 12 Mar 2018 12:26:53 +0100 [thread overview]
Message-ID: <CAJZ5v0hyk=jto8Wt0er==YmKEsgvfvZhO2wDbGOhxZaWWCNgBg@mail.gmail.com> (raw)
In-Reply-To: <1520853467-31653-1-git-send-email-anshuman.gupta@intel.com>
On Mon, Mar 12, 2018 at 12:17 PM, Anshuman Gupta
<anshuman.gupta@intel.com> wrote:
> Keep hdac-codec to be in runtime suspended while entering to suspend.
> If hdac-codec is already in runtime suspend state skip its power down
> sequence in prepare, power up sequence in complete phase.
>
> Avoid resuming hdac controller PCI device 00:1f.3 from runtime suspend
> state in case hdac-codec already in runtime-suspend state, this is
> unnecessary and block the direct complete even for hdac controller
> PCI device 00:1f.3.
>
> This enabled direct complete path for hdac-codec and PCI device 00:1f.3.
>
> Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
> ---
> sound/soc/codecs/hdac_hdmi.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/sound/soc/codecs/hdac_hdmi.c b/sound/soc/codecs/hdac_hdmi.c
> index f3b4f4d..810a8a6 100644
> --- a/sound/soc/codecs/hdac_hdmi.c
> +++ b/sound/soc/codecs/hdac_hdmi.c
> @@ -1852,6 +1852,8 @@ static int hdmi_codec_prepare(struct device *dev)
> struct hdac_ext_device *edev = to_hda_ext_device(dev);
> struct hdac_device *hdac = &edev->hdac;
>
> + if (pm_runtime_status_suspended(dev))
> + return 1;
This is racy in principle, because the runtime PM status can still
change after you've checked here.
But even if it isn't racy in practice, the following
pm_runtime_get_sync() becomes redundant after it, doesn't it?
> pm_runtime_get_sync(&edev->hdac.dev);
>
> /*
> @@ -1873,6 +1875,8 @@ static void hdmi_codec_complete(struct device *dev)
> struct hdac_hdmi_priv *hdmi = edev->private_data;
> struct hdac_device *hdac = &edev->hdac;
>
> + if (pm_runtime_status_suspended(dev))
> + return;
That, again, is somewhat fragile from the concurrency perspective.
> /* Power up afg */
> snd_hdac_codec_read(hdac, hdac->afg, 0, AC_VERB_SET_POWER_STATE,
> AC_PWRST_D0);
> --
> 2.7.4
>
next prev parent reply other threads:[~2018-03-12 11:26 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-12 11:17 [PATCH] [sound] hdac-codec runtime suspended at PM:Suspend Anshuman Gupta
2018-03-12 11:26 ` Rafael J. Wysocki [this message]
[not found] ` <5aa8fbe9.4251620a.c3daa.3711SMTPIN_ADDED_BROKEN@mx.google.com>
2018-03-14 10:53 ` Rafael J. Wysocki
[not found] ` <20180314153714.GA11459@anshuman.gupta@intel.com>
2018-03-15 10:42 ` Subhransu S. Prusty
[not found] ` <20180315153230.GA16531@anshuman.gupta@intel.com>
2018-03-26 7:03 ` Subhransu S. Prusty
2018-03-26 7:30 ` Takashi Iwai
2018-03-27 15:36 ` Lukas Wunner
2018-08-18 18:12 ` [PATCH v2 0/1] cover-letter " Anshuman Gupta
2018-08-18 18:12 ` [PATCH v2 1/1] " Anshuman Gupta
2018-08-28 16:34 ` Anshuman Gupta
2018-08-28 17:05 ` Takashi Iwai
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