[PATCH] ASoC: Don't defer resume work for AC97 codecs

[Mark Brown]

AC97 devices may have other drivers hanging off them directly so need to
have resumed when the resume function returns meaning that we can't defer
the resume - complete it immediately for them. Non-AC97 devices should
not have other drivers hanging directly off the ASoC devices.

We only really need the deferral for non-AC97 devices - it's there since
some I2C buses are very slow and non-AC97 codecs often have large numbers
of registers to restore and require delays to bring the codec up cleanly
leading to a substantial impact on overall resume time.

Signed-off-by: Mark Brown <broonie at opensource.wolfsonmicro.com>
Cc: stable at kernel.org
---
 sound/soc/soc-core.c |   18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 6e710f7..6c62d4a 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -767,11 +767,21 @@ static int soc_resume(struct platform_device *pdev)
 {
 	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
 	struct snd_soc_card *card = socdev->card;
+	struct snd_soc_dai *cpu_dai = card->dai_link[0].cpu_dai;
 
-	dev_dbg(socdev->dev, "scheduling resume work\n");
-
-	if (!schedule_work(&card->deferred_resume_work))
-		dev_err(socdev->dev, "resume work item may be lost\n");
+	/* AC97 devices might have other drivers hanging off them so
+	 * need to resume immediately.  Other drivers don't have that
+	 * problem and may take a substantial amount of time to resume
+	 * due to I/O costs and anti-pop so handle them out of line.
+	 */
+	if (cpu_dai->ac97_control) {
+		dev_dbg(socdev->dev, "Resuming AC97 immediately\n");
+		soc_resume_deferred(&card->deferred_resume_work);
+	} else {
+		dev_dbg(socdev->dev, "Scheduling resume work\n");
+		if (!schedule_work(&card->deferred_resume_work))
+			dev_err(socdev->dev, "resume work item may be lost\n");
+	}
 
 	return 0;
 }
-- 
1.6.2.1