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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: Thierry Reding <treding@nvidia.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2015-09-24 11:00:18 +02:00
parent 1f93e4a96c
commit 83510441bc
1 changed files with 25 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
sound/pci/hda/hda_tegra.c
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@ -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;
out_free:
return; /* no error return from async probe */
}
static int hda_tegra_remove(struct platform_device *pdev)