ASoC: Don't defer resume work for AC97 codecs (64ab9baa) · Commits · 戴 / test

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. Reported-by:

Russell King <linux@arm.linux.org.uk> Signed-off-by:

Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/soc-core.c

+14 −4

Original line number	Diff line number	Diff line
		@@ -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");

		/* 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;
		}

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