Messages in this thread | | | Date | Fri, 21 Jul 2023 15:55:43 +0100 | Subject | Re: [PATCH v1 10/11] ALSA: hda: cs35l41: Add device_link between HDA and cs35l41_hda | From | Stefan Binding <> |
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On 20/07/2023 15:21, Takashi Iwai wrote: > On Thu, 20 Jul 2023 15:31:46 +0200, > Stefan Binding wrote: >> To ensure consistency between the HDA core and the CS35L41 HDA >> driver, add a device_link between them. This ensures that the >> HDA core will suspend first, and resume second, meaning the >> amp driver will not miss any events from the playback hook from >> the HDA core during system suspend and resume. >> >> Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com> >> --- >> sound/pci/hda/cs35l41_hda.c | 13 ++++++++++++- >> 1 file changed, 12 insertions(+), 1 deletion(-) >> >> diff --git a/sound/pci/hda/cs35l41_hda.c b/sound/pci/hda/cs35l41_hda.c >> index 70aa819cfbd64..175378cdf9dfa 100644 >> --- a/sound/pci/hda/cs35l41_hda.c >> +++ b/sound/pci/hda/cs35l41_hda.c >> @@ -1063,6 +1063,7 @@ static int cs35l41_hda_bind(struct device *dev, struct device *master, void *mas >> { >> struct cs35l41_hda *cs35l41 = dev_get_drvdata(dev); >> struct hda_component *comps = master_data; >> + unsigned int sleep_flags; >> int ret = 0; >> >> if (!comps || cs35l41->index < 0 || cs35l41->index >= HDA_MAX_COMPONENTS) >> @@ -1102,6 +1103,11 @@ static int cs35l41_hda_bind(struct device *dev, struct device *master, void *mas >> >> mutex_unlock(&cs35l41->fw_mutex); >> >> + sleep_flags = lock_system_sleep(); >> + if (!device_link_add(&comps->codec->core.dev, cs35l41->dev, DL_FLAG_STATELESS)) >> + dev_warn(dev, "Unable to create device link\n"); >> + unlock_system_sleep(sleep_flags); > Is lock_system_sleep() mandatory for device_link_add()? The function > takes its rw lock for the race, I suppose.
I believe this is mandatory, to ensure we don't try to add the device link during a suspend/resume transition. Its probably unlikely that that would occur during the component bind, but just in case.
Thanks,
Stefan
> > > thanks, > > Takashi
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