From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:41941 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752629AbbJRCKp (ORCPT ); Sat, 17 Oct 2015 22:10:45 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thierry Reding , Takashi Iwai Subject: [PATCH 4.2 091/258] ALSA: hda/tegra - async probe for avoiding module loading deadlock Date: Sat, 17 Oct 2015 18:56:44 -0700 Message-Id: <20151018014734.518988495@linuxfoundation.org> In-Reply-To: <20151018014729.976101177@linuxfoundation.org> References: <20151018014729.976101177@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: stable-owner@vger.kernel.org List-ID: 4.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 83510441bc08bee201c0ded9d81da6dfd008d69a upstream. 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 Tested-by: Thierry Reding Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/pci/hda/hda_tegra.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) --- a/sound/pci/hda/hda_tegra.c +++ b/sound/pci/hda/hda_tegra.c @@ -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(stru 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 a /* * 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_c 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 platfo 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 platfo 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)