Re: [PATCH AUTOSEL 5.6 12/38] ALSA: hda: Skip controller resume if not needed

Takashi Iwai
2020-04-24T12:44:25Z

On Fri, 24 Apr 2020 14:22:10 +0200,
Sasha Levin wrote:
>
> From: Takashi Iwai <tiwai@suse.de>
>
> [ Upstream commit c4c8dd6ef807663e42a5f04ea77cd62029eb99fa ]
>
> The HD-audio controller does system-suspend and resume operations by
> directly calling its helpers __azx_runtime_suspend() and
> __azx_runtime_resume(). However, in general, we don't have to resume
> always the device fully at the system resume; typically, if a device
> has been runtime-suspended, we can leave it to runtime resume.
>
> Usually for achieving this, the driver would call
> pm_runtime_force_suspend() and pm_runtime_force_resume() pairs in the
> system suspend and resume ops. Unfortunately, this doesn't work for
> the resume path in our case. For handling the jack detection at the
> system resume, a child codec device may need the (literally) forcibly
> resume even if it's been runtime-suspended, and for that, the
> controller device must be also resumed even if it's been suspended.
>
> This patch is an attempt to improve the situation. It replaces the
> direct __azx_runtime_suspend()/_resume() calls with with
> pm_runtime_force_suspend() and pm_runtime_force_resume() with a slight
> trick as we've done for the codec side. More exactly:
>
> - azx_has_pm_runtime() check is dropped from azx_runtime_suspend() and
> azx_runtime_resume(), so that it can be properly executed from the
> system-suspend/resume path
>
> - The WAKEEN handling depends on the card's power state now; it's set
> and cleared only for the runtime-suspend
>
> - azx_resume() checks whether any codec may need the forcible resume
> beforehand. If the forcible resume is required, it does temporary
> PM refcount up/down for actually triggering the runtime resume.
>
> - A new helper function, hda_codec_need_resume(), is introduced for
> checking whether the codec needs a forcible runtime-resume, and the
> existing code is rewritten with that.
>
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=207043
> Link: https://lore.kernel.org/r/20200413082034.25166-6-tiwai@suse.de
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> Signed-off-by: Sasha Levin <sashal@kernel.org>

This commit is known to cause a regression, and the fix patch is
included in today's pull request. If we apply this, better to wait
for the next batch including its fix.

thanks,

Takashi

> ---
> include/sound/hda_codec.h | 5 +++++
> sound/pci/hda/hda_codec.c | 2 +-
> sound/pci/hda/hda_intel.c | 38 +++++++++++++++++++++++++++-----------
> 3 files changed, 33 insertions(+), 12 deletions(-)
>
> diff --git a/include/sound/hda_codec.h b/include/sound/hda_codec.h
> index 3ee8036f5436d..225154a4f2ed0 100644
> --- a/include/sound/hda_codec.h
> +++ b/include/sound/hda_codec.h
> @@ -494,6 +494,11 @@ void snd_hda_update_power_acct(struct hda_codec *codec);
> static inline void snd_hda_set_power_save(struct hda_bus *bus, int delay) {}
> #endif
>
> +static inline bool hda_codec_need_resume(struct hda_codec *codec)
> +{
> + return !codec->relaxed_resume && codec->jacktbl.used;
> +}
> +
> #ifdef CONFIG_SND_HDA_PATCH_LOADER
> /*
> * patch firmware
> diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
> index 53e7732ef7520..aed1f8188e662 100644
> --- a/sound/pci/hda/hda_codec.c
> +++ b/sound/pci/hda/hda_codec.c
> @@ -2951,7 +2951,7 @@ static int hda_codec_runtime_resume(struct device *dev)
> static int hda_codec_force_resume(struct device *dev)
> {
> struct hda_codec *codec = dev_to_hda_codec(dev);
> - bool forced_resume = !codec->relaxed_resume && codec->jacktbl.used;
> + bool forced_resume = hda_codec_need_resume(codec);
> int ret;
>
> /* The get/put pair below enforces the runtime resume even if the
> diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> index aa0be85614b6c..02c6308502b1e 100644
> --- a/sound/pci/hda/hda_intel.c
> +++ b/sound/pci/hda/hda_intel.c
> @@ -1027,7 +1027,7 @@ static int azx_suspend(struct device *dev)
> chip = card->private_data;
> bus = azx_bus(chip);
> snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
> - __azx_runtime_suspend(chip);
> + pm_runtime_force_suspend(dev);
> if (bus->irq >= 0) {
> free_irq(bus->irq, chip);
> bus->irq = -1;
> @@ -1044,7 +1044,9 @@ static int azx_suspend(struct device *dev)
> static int azx_resume(struct device *dev)
> {
> struct snd_card *card = dev_get_drvdata(dev);
> + struct hda_codec *codec;
> struct azx *chip;
> + bool forced_resume = false;
>
> if (!azx_is_pm_ready(card))
> return 0;
> @@ -1055,7 +1057,20 @@ static int azx_resume(struct device *dev)
> chip->msi = 0;
> if (azx_acquire_irq(chip, 1) < 0)
> return -EIO;
> - __azx_runtime_resume(chip, false);
> +
> + /* check for the forced resume */
> + list_for_each_codec(codec, &chip->bus) {
> + if (hda_codec_need_resume(codec)) {
> + forced_resume = true;
> + break;
> + }
> + }
> +
> + if (forced_resume)
> + pm_runtime_get_noresume(dev);
> + pm_runtime_force_resume(dev);
> + if (forced_resume)
> + pm_runtime_put(dev);
> snd_power_change_state(card, SNDRV_CTL_POWER_D0);
>
> trace_azx_resume(chip);
> @@ -1102,12 +1117,12 @@ static int azx_runtime_suspend(struct device *dev)
> if (!azx_is_pm_ready(card))
> return 0;
> chip = card->private_data;
> - if (!azx_has_pm_runtime(chip))
> - return 0;
>
> /* enable controller wake up event */
> - azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) |
> - STATESTS_INT_MASK);
> + if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0) {
> + azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) |
> + STATESTS_INT_MASK);
> + }
>
> __azx_runtime_suspend(chip);
> trace_azx_runtime_suspend(chip);
> @@ -1118,17 +1133,18 @@ static int azx_runtime_resume(struct device *dev)
> {
> struct snd_card *card = dev_get_drvdata(dev);
> struct azx *chip;
> + bool from_rt = snd_power_get_state(card) == SNDRV_CTL_POWER_D0;
>
> if (!azx_is_pm_ready(card))
> return 0;
> chip = card->private_data;
> - if (!azx_has_pm_runtime(chip))
> - return 0;
> - __azx_runtime_resume(chip, true);
> + __azx_runtime_resume(chip, from_rt);
>
> /* disable controller Wake Up event*/
> - azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) &
> - ~STATESTS_INT_MASK);
> + if (from_rt) {
> + azx_writew(chip, WAKEEN, azx_readw(chip, WAKEEN) &
> + ~STATESTS_INT_MASK);
> + }
>
> trace_azx_runtime_resume(chip);
> return 0;
> --
> 2.20.1
>