target/linux/s3c24xx/patches-2.6.24/1182-ASoC-Don-t-block-system-resume.patch

   1 From 2219855aa7835e082ec134fafd9ddba84589d345 Mon Sep 17 00:00:00 2001
   2 From: Andy Green <andy@openmoko.com>
   3 Date: Wed, 2 Jul 2008 22:39:33 +0100
   4 Subject: [PATCH] ASoC: Don't block system resume
   5
   6 On OpenMoko soc-audio resume is taking 700ms of the whole resume time of
   7 1.3s, dominated by writes to the codec over I2C.  This patch shunts the
   8 resume guts into a workqueue which then is done asynchronously.
   9
  10 The "card" is locked using the ALSA power state APIs as suggested by
  11 Mark Brown.
  12
  13 [Added fix for race with resume to suspend and fixed a couple of nits
  14 from checkpatch -- broonie.]
  15
  16 Signed-off-by: Andy Green <andy@openmoko.com>
  17 Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
  18 ---
  19  include/sound/soc.h  |    1 +
  20  sound/soc/soc-core.c |   52 ++++++++++++++++++++++++++++++++++++++++++++-----
  21  2 files changed, 47 insertions(+), 6 deletions(-)
  22
  23 diff --git a/include/sound/soc.h b/include/sound/soc.h
  24 index aedb348..2d6c0eb 100644
  25 --- a/include/sound/soc.h
  26 +++ b/include/sound/soc.h
  27 @@ -442,6 +442,7 @@ struct snd_soc_device {
  28         struct snd_soc_codec *codec;
  29         struct snd_soc_codec_device *codec_dev;
  30         struct delayed_work delayed_work;
  31 +       struct work_struct deferred_resume_work;
  32         void *codec_data;
  33  };
  34
  35 diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
  36 index 9e20333..e96930e 100644
  37 --- a/sound/soc/soc-core.c
  38 +++ b/sound/soc/soc-core.c
  39 @@ -632,6 +632,16 @@ static int soc_suspend(struct platform_device *pdev, pm_message_t state)
  40         struct snd_soc_codec *codec = socdev->codec;
  41         int i;
  42
  43 +       /* Due to the resume being scheduled into a workqueue we could
  44 +       * suspend before that's finished - wait for it to complete.
  45 +        */
  46 +       snd_power_lock(codec->card);
  47 +       snd_power_wait(codec->card, SNDRV_CTL_POWER_D0);
  48 +       snd_power_unlock(codec->card);
  49 +
  50 +       /* we're going to block userspace touching us until resume completes */
  51 +       snd_power_change_state(codec->card, SNDRV_CTL_POWER_D3hot);
  52 +
  53         /* mute any active DAC's */
  54         for(i = 0; i < machine->num_links; i++) {
  55                 struct snd_soc_codec_dai *dai = machine->dai_link[i].codec_dai;
  56 @@ -684,16 +694,27 @@ static int soc_suspend(struct platform_device *pdev, pm_message_t state)
  57         return 0;
  58  }
  59
  60 -/* powers up audio subsystem after a suspend */
  61 -static int soc_resume(struct platform_device *pdev)
  62 +/* deferred resume work, so resume can complete before we finished
  63 + * setting our codec back up, which can be very slow on I2C
  64 + */
  65 +static void soc_resume_deferred(struct work_struct *work)
  66  {
  67 -       struct snd_soc_device *socdev = platform_get_drvdata(pdev);
  68 -       struct snd_soc_machine *machine = socdev->machine;
  69 -       struct snd_soc_platform *platform = socdev->platform;
  70 -       struct snd_soc_codec_device *codec_dev = socdev->codec_dev;
  71 +       struct snd_soc_device *socdev = container_of(work,
  72 +                                                    struct snd_soc_device,
  73 +                                                    deferred_resume_work);
  74 +       struct snd_soc_machine *machine = socdev->machine;
  75 +       struct snd_soc_platform *platform = socdev->platform;
  76 +       struct snd_soc_codec_device *codec_dev = socdev->codec_dev;
  77         struct snd_soc_codec *codec = socdev->codec;
  78 +       struct platform_device *pdev = to_platform_device(socdev->dev);
  79         int i;
  80
  81 +       /* our power state is still SNDRV_CTL_POWER_D3hot from suspend time,
  82 +        * so userspace apps are blocked from touching us
  83 +        */
  84 +
  85 +       dev_info(socdev->dev, "starting resume work\n");
  86 +
  87         if (machine->resume_pre)
  88                 machine->resume_pre(pdev);
  89
  90 @@ -735,6 +756,22 @@ static int soc_resume(struct platform_device *pdev)
  91         if (machine->resume_post)
  92                 machine->resume_post(pdev);
  93
  94 +       dev_info(socdev->dev, "resume work completed\n");
  95 +
  96 +       /* userspace can access us now we are back as we were before */
  97 +       snd_power_change_state(codec->card, SNDRV_CTL_POWER_D0);
  98 +}
  99 +
 100 +/* powers up audio subsystem after a suspend */
 101 +static int soc_resume(struct platform_device *pdev)
 102 +{
 103 +       struct snd_soc_device *socdev = platform_get_drvdata(pdev);
 104 +
 105 +       dev_info(socdev->dev, "scheduling resume work\n");
 106 +
 107 +       if (!schedule_work(&socdev->deferred_resume_work))
 108 +               dev_err(socdev->dev, "work item may be lost\n");
 109 +
 110         return 0;
 111  }
 112
 113 @@ -781,6 +818,9 @@ static int soc_probe(struct platform_device *pdev)
 114
 115         /* DAPM stream work */
 116         INIT_DELAYED_WORK(&socdev->delayed_work, close_delayed_work);
 117 +       /* deferred resume work */
 118 +       INIT_WORK(&socdev->deferred_resume_work, soc_resume_deferred);
 119 +
 120         return 0;
 121
 122  platform_err:
 123 --
 124 1.5.6.5
 125