| Message ID | 20230902210621.1184693-10-cristian.ciocaltea@collabora.com |
|---|---|
| State | New |
| Headers | show |
| Series | Improve CS35l41 ALSA SoC audio driver | expand |
On Sun, Sep 03, 2023 at 12:06:21AM +0300, Cristian Ciocaltea wrote: > Simplify runtime PM during probe by converting pm_runtime_enable() to > the managed version. > > Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com> > --- > @@ -1376,7 +1379,6 @@ void cs35l41_remove(struct cs35l41_private *cs35l41) > cancel_work_sync(&cs35l41->mdsync_up_work); > > pm_runtime_get_sync(cs35l41->dev); > - pm_runtime_disable(cs35l41->dev); > > regmap_write(cs35l41->regmap, CS35L41_IRQ1_MASK1, 0xFFFFFFFF); > if (cs35l41->hw_cfg.bst_type == CS35L41_SHD_BOOST_PASS || Are we sure this is safe? The remove handler appears to be written to disable pm_runtime at the start presumably to stop the resume/suspend handler running during the remove callback. Whereas after this change the pm_runtime isn't disabled until after the remove callback has run. Does this open a window were we could get an erroneous pm_runtime suspend after the pm_runtime_put_noidle? Thanks, Charles
On 9/5/23 12:45, Charles Keepax wrote: > On Sun, Sep 03, 2023 at 12:06:21AM +0300, Cristian Ciocaltea wrote: >> Simplify runtime PM during probe by converting pm_runtime_enable() to >> the managed version. >> >> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com> >> --- >> @@ -1376,7 +1379,6 @@ void cs35l41_remove(struct cs35l41_private *cs35l41) >> cancel_work_sync(&cs35l41->mdsync_up_work); >> >> pm_runtime_get_sync(cs35l41->dev); >> - pm_runtime_disable(cs35l41->dev); >> >> regmap_write(cs35l41->regmap, CS35L41_IRQ1_MASK1, 0xFFFFFFFF); >> if (cs35l41->hw_cfg.bst_type == CS35L41_SHD_BOOST_PASS || > > Are we sure this is safe? The remove handler appears to be > written to disable pm_runtime at the start presumably to stop the > resume/suspend handler running during the remove callback. > Whereas after this change the pm_runtime isn't disabled until > after the remove callback has run. Does this open a window were > we could get an erroneous pm_runtime suspend after the > pm_runtime_put_noidle? I've just made a test adding a 6s sleep before returning from the remove handler: [14444.894316] cs35l41 spi-VLV1776:00: Runtime resume [14444.894469] cs35l41 spi-VLV1776:00: sleep 6s before return of cs35l41_remove() [14448.338994] cs35l41 spi-VLV1776:00: Runtime suspend [14451.079649] cs35l41 spi-VLV1776:00: return from cs35l41_remove() [14451.080129] cs35l41 spi-VLV1776:00: Runtime resume [14451.080165] cs35l41 spi-VLV1776:00: ASoC: Unregistered DAI 'cs35l41-pcm' [14451.080181] cs35l41 spi-VLV1776:00: Runtime suspend [14451.813639] acp5x_i2s_playcap acp5x_i2s_playcap.0: ASoC: Unregistered DAI 'acp5x_i2s_playcap.0' As expected, suspend triggered, but a resume was issued later, before DAI got unregistered. I didn't notice any issues while repeating the test several times, hence I wonder what would be the reason to prevent getting suspend/resume events at this point? Thanks, Cristian
On Tue, Sep 05, 2023 at 10:15:46PM +0300, Cristian Ciocaltea wrote: > On 9/5/23 12:45, Charles Keepax wrote: > > On Sun, Sep 03, 2023 at 12:06:21AM +0300, Cristian Ciocaltea wrote: > >> Simplify runtime PM during probe by converting pm_runtime_enable() to > >> the managed version. > >> > >> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com> > >> --- > >> @@ -1376,7 +1379,6 @@ void cs35l41_remove(struct cs35l41_private *cs35l41) > >> cancel_work_sync(&cs35l41->mdsync_up_work); > >> > >> pm_runtime_get_sync(cs35l41->dev); > >> - pm_runtime_disable(cs35l41->dev); > >> > >> regmap_write(cs35l41->regmap, CS35L41_IRQ1_MASK1, 0xFFFFFFFF); > >> if (cs35l41->hw_cfg.bst_type == CS35L41_SHD_BOOST_PASS || > > > > Are we sure this is safe? The remove handler appears to be > > written to disable pm_runtime at the start presumably to stop the > > resume/suspend handler running during the remove callback. > > Whereas after this change the pm_runtime isn't disabled until > > after the remove callback has run. Does this open a window were > > we could get an erroneous pm_runtime suspend after the > > pm_runtime_put_noidle? > > I've just made a test adding a 6s sleep before returning from the remove > handler: > > [14444.894316] cs35l41 spi-VLV1776:00: Runtime resume > [14444.894469] cs35l41 spi-VLV1776:00: sleep 6s before return of cs35l41_remove() > [14448.338994] cs35l41 spi-VLV1776:00: Runtime suspend > [14451.079649] cs35l41 spi-VLV1776:00: return from cs35l41_remove() > [14451.080129] cs35l41 spi-VLV1776:00: Runtime resume > [14451.080165] cs35l41 spi-VLV1776:00: ASoC: Unregistered DAI 'cs35l41-pcm' > [14451.080181] cs35l41 spi-VLV1776:00: Runtime suspend > [14451.813639] acp5x_i2s_playcap acp5x_i2s_playcap.0: ASoC: Unregistered DAI 'acp5x_i2s_playcap.0' > > As expected, suspend triggered, but a resume was issued later, before DAI > got unregistered. > > I didn't notice any issues while repeating the test several times, hence > I wonder what would be the reason to prevent getting suspend/resume events > at this point? The enter/exit hibernate code might run, which at the very least might result in a bunch of unexpected and failing bus traffic. Having a bit of a poke through the code, I guess the most dangerous thing would if you actually got as far as an extra runtime resume. This might cause cs35l41_init_boost to run which would undo the work done by the call to cs35l41_safe_reset in remove, which could leave the boost in a dangerous state when we enable reset/power down the supplies, which I think was not considered good. But its just likely simpler/cleaner if we don't have to think about all the possible implications of such things by just not allowing it to happen. Thanks, Charles
On 9/6/23 19:37, Charles Keepax wrote: > On Tue, Sep 05, 2023 at 10:15:46PM +0300, Cristian Ciocaltea wrote: >> On 9/5/23 12:45, Charles Keepax wrote: >>> On Sun, Sep 03, 2023 at 12:06:21AM +0300, Cristian Ciocaltea wrote: >>>> Simplify runtime PM during probe by converting pm_runtime_enable() to >>>> the managed version. >>>> >>>> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com> >>>> --- >>>> @@ -1376,7 +1379,6 @@ void cs35l41_remove(struct cs35l41_private *cs35l41) >>>> cancel_work_sync(&cs35l41->mdsync_up_work); >>>> >>>> pm_runtime_get_sync(cs35l41->dev); >>>> - pm_runtime_disable(cs35l41->dev); >>>> >>>> regmap_write(cs35l41->regmap, CS35L41_IRQ1_MASK1, 0xFFFFFFFF); >>>> if (cs35l41->hw_cfg.bst_type == CS35L41_SHD_BOOST_PASS || >>> >>> Are we sure this is safe? The remove handler appears to be >>> written to disable pm_runtime at the start presumably to stop the >>> resume/suspend handler running during the remove callback. >>> Whereas after this change the pm_runtime isn't disabled until >>> after the remove callback has run. Does this open a window were >>> we could get an erroneous pm_runtime suspend after the >>> pm_runtime_put_noidle? >> >> I've just made a test adding a 6s sleep before returning from the remove >> handler: >> >> [14444.894316] cs35l41 spi-VLV1776:00: Runtime resume >> [14444.894469] cs35l41 spi-VLV1776:00: sleep 6s before return of cs35l41_remove() >> [14448.338994] cs35l41 spi-VLV1776:00: Runtime suspend >> [14451.079649] cs35l41 spi-VLV1776:00: return from cs35l41_remove() >> [14451.080129] cs35l41 spi-VLV1776:00: Runtime resume >> [14451.080165] cs35l41 spi-VLV1776:00: ASoC: Unregistered DAI 'cs35l41-pcm' >> [14451.080181] cs35l41 spi-VLV1776:00: Runtime suspend >> [14451.813639] acp5x_i2s_playcap acp5x_i2s_playcap.0: ASoC: Unregistered DAI 'acp5x_i2s_playcap.0' >> >> As expected, suspend triggered, but a resume was issued later, before DAI >> got unregistered. >> >> I didn't notice any issues while repeating the test several times, hence >> I wonder what would be the reason to prevent getting suspend/resume events >> at this point? > > The enter/exit hibernate code might run, which at the very > least might result in a bunch of unexpected and failing bus > traffic. Having a bit of a poke through the code, I guess the > most dangerous thing would if you actually got as far as an > extra runtime resume. This might cause cs35l41_init_boost > to run which would undo the work done by the call to > cs35l41_safe_reset in remove, which could leave the boost in a > dangerous state when we enable reset/power down the supplies, > which I think was not considered good. But its just likely > simpler/cleaner if we don't have to think about all the > possible implications of such things by just not allowing > it to happen. Agree, let's keep it simple. I will revert the change and instead ensure a proper cleanup of pm_runtime_use_autosuspend(), according to the documentation: "It's important to undo this with pm_runtime_dont_use_autosuspend() at driver exit time unless your driver initially enabled pm_runtime with devm_pm_runtime_enable() (which handles it for you)." Thanks for the clarifications, Cristian
On Wed, Sep 06, 2023 at 10:55:28PM +0300, Cristian Ciocaltea wrote: > On 9/6/23 19:37, Charles Keepax wrote: > > On Tue, Sep 05, 2023 at 10:15:46PM +0300, Cristian Ciocaltea wrote: > >> On 9/5/23 12:45, Charles Keepax wrote: > >>> On Sun, Sep 03, 2023 at 12:06:21AM +0300, Cristian Ciocaltea wrote: > Agree, let's keep it simple. I will revert the change and instead ensure > a proper cleanup of pm_runtime_use_autosuspend(), according to the > documentation: > > "It's important to undo this with pm_runtime_dont_use_autosuspend() at > driver exit time unless your driver initially enabled pm_runtime with > devm_pm_runtime_enable() (which handles it for you)." > Good spot was not aware of that, thank you. Thanks, Charles
diff --git a/sound/soc/codecs/cs35l41.c b/sound/soc/codecs/cs35l41.c index 5655758063ae..2e5b4633e98d 100644 --- a/sound/soc/codecs/cs35l41.c +++ b/sound/soc/codecs/cs35l41.c @@ -1340,7 +1340,12 @@ int cs35l41_probe(struct cs35l41_private *cs35l41, const struct cs35l41_hw_cfg * pm_runtime_mark_last_busy(cs35l41->dev); pm_runtime_set_active(cs35l41->dev); pm_runtime_get_noresume(cs35l41->dev); - pm_runtime_enable(cs35l41->dev); + + ret = devm_pm_runtime_enable(cs35l41->dev); + if (ret < 0) { + dev_err_probe(cs35l41->dev, ret, "Failed to enable PM runtime\n"); + goto err_pm; + } ret = devm_snd_soc_register_component(cs35l41->dev, &soc_component_dev_cs35l41, @@ -1358,9 +1363,7 @@ int cs35l41_probe(struct cs35l41_private *cs35l41, const struct cs35l41_hw_cfg * return 0; err_pm: - pm_runtime_disable(cs35l41->dev); pm_runtime_put_noidle(cs35l41->dev); - wm_adsp2_remove(&cs35l41->dsp); err: cs35l41_safe_reset(cs35l41->regmap, cs35l41->hw_cfg.bst_type); @@ -1376,7 +1379,6 @@ void cs35l41_remove(struct cs35l41_private *cs35l41) cancel_work_sync(&cs35l41->mdsync_up_work); pm_runtime_get_sync(cs35l41->dev); - pm_runtime_disable(cs35l41->dev); regmap_write(cs35l41->regmap, CS35L41_IRQ1_MASK1, 0xFFFFFFFF); if (cs35l41->hw_cfg.bst_type == CS35L41_SHD_BOOST_PASS ||
Simplify runtime PM during probe by converting pm_runtime_enable() to the managed version. Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com> --- sound/soc/codecs/cs35l41.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)