Re: [PATCH v2] ALSA: hda/tegra: enable clock during probe

Jon Hunter
2019-01-25T11:42:16Z

On 25/01/2019 11:06, Sameer Pujar wrote:
> If CONFIG_PM is disabled or runtime PM calls are forbidden, the clocks
> will not be ON. This could cause issue during probe, where hda init
> setup is done. This patch enables clocks unconditionally during probe.
>
> Along with above, follwoing changes are done.
> * enable runtime PM before exiting from probe work. This helps to avoid
> usage of pm_runtime_get_sync/pm_runtime_put() in probe work.
> * hda_tegra_disable_clocks() is moved out of CONFIG_PM_SLEEP check.
> * runtime PM callbacks moved out of CONFIG_PM check
>
> Signed-off-by: Sameer Pujar <spujar@nvidia.com>
> Reviewed-by: Ravindra Lokhande <rlokhande@nvidia.com>
> Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
> ---
> sound/pci/hda/hda_tegra.c | 26 +++++++++++++++++---------
> 1 file changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/sound/pci/hda/hda_tegra.c b/sound/pci/hda/hda_tegra.c
> index c8d18dc..ba6175f 100644
> --- a/sound/pci/hda/hda_tegra.c
> +++ b/sound/pci/hda/hda_tegra.c
> @@ -219,7 +219,6 @@ static int hda_tegra_enable_clocks(struct hda_tegra *data)
> return rc;
> }
>
> -#ifdef CONFIG_PM_SLEEP
> static void hda_tegra_disable_clocks(struct hda_tegra *data)
> {
> clk_disable_unprepare(data->hda2hdmi_clk);
> @@ -227,6 +226,7 @@ static void hda_tegra_disable_clocks(struct hda_tegra *data)
> clk_disable_unprepare(data->hda_clk);
> }
>
> +#ifdef CONFIG_PM_SLEEP
> /*
> * power management
> */
> @@ -257,7 +257,6 @@ static int hda_tegra_resume(struct device *dev)
> }
> #endif /* CONFIG_PM_SLEEP */
>
> -#ifdef CONFIG_PM
> static int hda_tegra_runtime_suspend(struct device *dev)
> {
> struct snd_card *card = dev_get_drvdata(dev);
> @@ -283,7 +282,7 @@ static int hda_tegra_runtime_resume(struct device *dev)
> int rc;
>
> rc = hda_tegra_enable_clocks(hda);
> - if (rc != 0)
> + if (rc)
> return rc;
> if (chip && chip->running) {
> hda_tegra_init(hda);
> @@ -292,7 +291,6 @@ static int hda_tegra_runtime_resume(struct device *dev)
>
> return 0;
> }
> -#endif /* CONFIG_PM */
>
> static const struct dev_pm_ops hda_tegra_pm = {
> SET_SYSTEM_SLEEP_PM_OPS(hda_tegra_suspend, hda_tegra_resume)
> @@ -551,9 +549,9 @@ static int hda_tegra_probe(struct platform_device *pdev)
>
> dev_set_drvdata(&pdev->dev, card);
>
> - pm_runtime_enable(hda->dev);
> - if (!azx_has_pm_runtime(chip))
> - pm_runtime_forbid(hda->dev);
> + err = hda_tegra_enable_clocks(hda);
> + if (err)
> + goto out_free;
>
> schedule_work(&hda->probe_work);
>
> @@ -571,7 +569,6 @@ static void hda_tegra_probe_work(struct work_struct *work)
> struct platform_device *pdev = to_platform_device(hda->dev);
> int err;
>
> - pm_runtime_get_sync(hda->dev);
> err = hda_tegra_first_init(chip, pdev);
> if (err < 0)
> goto out_free;
> @@ -592,8 +589,15 @@ static void hda_tegra_probe_work(struct work_struct *work)
> chip->running = 1;
> snd_hda_set_power_save(&chip->bus, power_save * 1000);
>
> + /* set device state as active */
> + if (pm_runtime_set_active(hda->dev) < 0)
> + goto out_free;
> + /* enable runtime PM */
> + pm_runtime_enable(hda->dev);
> + if (!azx_has_pm_runtime(chip))
> + pm_runtime_forbid(hda->dev);
> +
> out_free:
> - pm_runtime_put(hda->dev);
> return; /* no error return from async probe */
> }
>
> @@ -603,6 +607,10 @@ static int hda_tegra_remove(struct platform_device *pdev)
>
> ret = snd_card_free(dev_get_drvdata(&pdev->dev));
> pm_runtime_disable(&pdev->dev);
> + if (!pm_runtime_status_suspended(&pdev->dev)) {
> + hda_tegra_runtime_suspend(&pdev->dev);
> + pm_runtime_set_suspended(&pdev->dev);
> + }

I think that we need to be consistent in the above with what is done in
the probe. If in the probe we call hda_tegra_enable_clocks(), then here
we should call hda_tegra_disable_clocks(). However, my preference is
still to all hda_tegra_runtime_resume() in probe and then leave the
above as-is. Let's see what everyone else thinks.

Cheers
Jon

--
nvpublic