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Commit 83510441 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: hda/tegra - async probe for avoiding module loading deadlock 



The Tegra HD-audio controller driver causes deadlocks when loaded as a
module since the driver invokes request_module() at binding with the
codec driver.  This patch works around it by deferring the probe in a
work like Intel HD-audio controller driver does.  Although hovering
the codec probe stuff into udev would be a better solution, it may
cause other regressions, so let's try this band-aid fix until the more
proper solution gets landed.

Reported-by: default avatarThierry Reding <treding@nvidia.com>
Tested-by: default avatarThierry Reding <treding@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 1f93e4a9

sound/pci/hda/hda_tegra.c

+25 −5
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ struct hda_tegra { 
	struct clk *hda2codec_2x_clk;

	struct clk *hda2hdmi_clk;

	void __iomem *regs;

	struct work_struct probe_work;

};



#ifdef CONFIG_PM
@@ -294,7 +295,9 @@ static int hda_tegra_dev_disconnect(struct snd_device *device) 
static int hda_tegra_dev_free(struct snd_device *device)

{

	struct azx *chip = device->device_data;

	struct hda_tegra *hda = container_of(chip, struct hda_tegra, chip);



	cancel_work_sync(&hda->probe_work);

	if (azx_bus(chip)->chip_init) {

		azx_stop_all_streams(chip);

		azx_stop_chip(chip);
@@ -426,6 +429,9 @@ static int hda_tegra_first_init(struct azx *chip, struct platform_device *pdev) 
/*

 * constructor

 */



static void hda_tegra_probe_work(struct work_struct *work);



static int hda_tegra_create(struct snd_card *card,

			    unsigned int driver_caps,

			    struct hda_tegra *hda)
@@ -452,6 +458,8 @@ static int hda_tegra_create(struct snd_card *card, 
	chip->single_cmd = false;

	chip->snoop = true;



	INIT_WORK(&hda->probe_work, hda_tegra_probe_work);



	err = azx_bus_init(chip, NULL, &hda_tegra_io_ops);

	if (err < 0)

		return err;
@@ -499,6 +507,21 @@ static int hda_tegra_probe(struct platform_device *pdev) 
	card->private_data = chip;



	dev_set_drvdata(&pdev->dev, card);

	schedule_work(&hda->probe_work);



	return 0;



out_free:

	snd_card_free(card);

	return err;

}



static void hda_tegra_probe_work(struct work_struct *work)

{

	struct hda_tegra *hda = container_of(work, struct hda_tegra, probe_work);

	struct azx *chip = &hda->chip;

	struct platform_device *pdev = to_platform_device(hda->dev);

	int err;



	err = hda_tegra_first_init(chip, pdev);

	if (err < 0)
@@ -520,11 +543,8 @@ static int hda_tegra_probe(struct platform_device *pdev) 
	chip->running = 1;

	snd_hda_set_power_save(&chip->bus, power_save * 1000);



	return 0;



 out_free:

	snd_card_free(card);

	return err;

	return; /* no error return from async probe */

}



static int hda_tegra_remove(struct platform_device *pdev)