From: Andy Green andy@openmoko.com

On OpenMoko soc-audio resume is taking 700ms of the whole resume time of 1.3s, dominated by writes to the codec over I2C. This patch shunts the resume guts into a workqueue which then is done asynchronously.

The "card" is locked using the ALSA power state APIs as suggested by Mark Brown.

[Added fix for race with resume to suspend and fixed a couple of nits from checkpatch -- broonie.]

Signed-off-by: Andy Green andy@openmoko.com Signed-off-by: Mark Brown broonie@opensource.wolfsonmicro.com --- include/sound/soc.h | 1 + sound/soc/soc-core.c | 46 +++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h index 1f5c621..340223a 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -510,6 +510,7 @@ struct snd_soc_device { struct snd_soc_codec *codec; struct snd_soc_codec_device *codec_dev; struct delayed_work delayed_work; + struct work_struct deferred_resume_work; void *codec_data; };

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index c96a618..b931039 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -639,6 +639,16 @@ static int soc_suspend(struct platform_device *pdev, pm_message_t state) struct snd_soc_codec *codec = socdev->codec; int i;

+ /* Due to the resume being scheduled into a workqueue we could + * suspend before that's finished - wait for it to complete. + */ + snd_power_lock(codec->card); + snd_power_wait(codec->card, SNDRV_CTL_POWER_D0); + snd_power_unlock(codec->card); + + /* we're going to block userspace touching us until resume completes */ + snd_power_change_state(codec->card, SNDRV_CTL_POWER_D3hot); + /* mute any active DAC's */ for (i = 0; i < machine->num_links; i++) { struct snd_soc_codec_dai *dai = machine->dai_link[i].codec_dai; @@ -691,16 +701,27 @@ static int soc_suspend(struct platform_device *pdev, pm_message_t state) return 0; }

-/* powers up audio subsystem after a suspend */ -static int soc_resume(struct platform_device *pdev) +/* deferred resume work, so resume can complete before we finished + * setting our codec back up, which can be very slow on I2C + */ +static void soc_resume_deferred(struct work_struct *work) { - struct snd_soc_device *socdev = platform_get_drvdata(pdev); + struct snd_soc_device *socdev = container_of(work, + struct snd_soc_device, + deferred_resume_work); struct snd_soc_machine *machine = socdev->machine; struct snd_soc_platform *platform = socdev->platform; struct snd_soc_codec_device *codec_dev = socdev->codec_dev; struct snd_soc_codec *codec = socdev->codec; + struct platform_device *pdev = to_platform_device(socdev->dev); int i;

+ /* our power state is still SNDRV_CTL_POWER_D3hot from suspend time, + * so userspace apps are blocked from touching us + */ + + dev_info(socdev->dev, "starting resume work\n"); + if (machine->resume_pre) machine->resume_pre(pdev);

@@ -742,6 +763,22 @@ static int soc_resume(struct platform_device *pdev) if (machine->resume_post) machine->resume_post(pdev);

+ dev_info(socdev->dev, "resume work completed\n"); + + /* userspace can access us now we are back as we were before */ + snd_power_change_state(codec->card, SNDRV_CTL_POWER_D0); +} + +/* powers up audio subsystem after a suspend */ +static int soc_resume(struct platform_device *pdev) +{ + struct snd_soc_device *socdev = platform_get_drvdata(pdev); + + dev_info(socdev->dev, "scheduling resume work\n"); + + if (!schedule_work(&socdev->deferred_resume_work)) + dev_err(socdev->dev, "work item may be lost\n"); + return 0; }

@@ -788,6 +825,9 @@ static int soc_probe(struct platform_device *pdev)

/* DAPM stream work */ INIT_DELAYED_WORK(&socdev->delayed_work, close_delayed_work); + /* deferred resume work */ + INIT_WORK(&socdev->deferred_resume_work, soc_resume_deferred); + return 0;

platform_err: