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Message-ID: <2575909c-635e-3c79-23f7-7f638fdd8fc0@nvidia.com>
Date: Fri, 25 Jan 2019 13:15:22 +0000
From: Jon Hunter <jonathanh@...dia.com>
To: Sameer Pujar <spujar@...dia.com>, <perex@...ex.cz>,
<tiwai@...e.com>, <pierre-louis.bossart@...ux.intel.com>
CC: <thierry.reding@...il.com>, <rlokhande@...dia.com>,
<sharadg@...dia.com>, <mkumard@...dia.com>,
<alsa-devel@...a-project.org>, <linux-tegra@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] ALSA: hda/tegra: enable clock during probe
On 25/01/2019 12:19, Sameer Pujar wrote:
>
> On 1/25/2019 5:12 PM, Jon Hunter wrote:
>> 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@...dia.com>
>>> Reviewed-by: Ravindra Lokhande <rlokhande@...dia.com>
>>> Reviewed-by: Jon Hunter <jonathanh@...dia.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.
> Though it is good to have the handling at a single place, it is slightly
> confusing to call
> runtime_resume() in probe. When runtime PM is not yet enabled, why call
> something that is related
> to it(not logically but intuitively)!
I still don't think that it is confusing, the name of the function is
called hda_tegra_runtime_resume and does what is says on the tin (ie.
resumes the device at runtime).
Furthermore, I think it is completely logical that if pm-runtime is not
enabled, we manually call it. The benefit is that we have single
function for resuming the device for all circumstances.
Cheers
Jon
--
nvpublic
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