[alsa-devel] [PATCH] ASoC: codec: hdac_hdmi add device_link to card device

[Yang, Libin]

Hi Pierre,

>-----Original Message-----
>From: Pierre-Louis Bossart [mailto:pierre-louis.bossart at linux.intel.com]
>Sent: Friday, April 12, 2019 11:00 AM
>To: Yang, Libin <libin.yang at intel.com>; alsa-devel at alsa-project.org;
>tiwai at suse.de; broonie at kernel.org
>Subject: Re: [alsa-devel] [PATCH] ASoC: codec: hdac_hdmi add device_link to
>card device
>
>On 4/11/19 9:40 PM, libin.yang at intel.com wrote:
>> From: Libin Yang <libin.yang at intel.com>
>>
>> In resume from S3, HDAC HDMI codec driver dapm event callback may be
>> operated before HDMI codec driver turns on the display audio power
>> domain because of the contest between display driver and hdmi codec
>driver.
>>
>> This patch adds the device_link between soc card device (consumer) and
>> hdmi codec device (supplier) to make sure the sequence is always correct.
>>
>> Signed-off-by: Libin Yang <libin.yang at intel.com>
>> ---
>>   sound/soc/codecs/hdac_hdmi.c | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
>> diff --git a/sound/soc/codecs/hdac_hdmi.c
>> b/sound/soc/codecs/hdac_hdmi.c index 5eeb0fe..8bb883e 100644
>> --- a/sound/soc/codecs/hdac_hdmi.c
>> +++ b/sound/soc/codecs/hdac_hdmi.c
>> @@ -1855,6 +1855,15 @@ static int hdmi_codec_probe(struct
>snd_soc_component *component)
>>   	hdmi->card = dapm->card->snd_card;
>>
>>   	/*
>> +	 * Setup a device_link between card device and HDMI codec device.
>> +	 * The card device is the consumer and the HDMI codec device is
>> +	 * the supplier. With this setting, we can make sure that the audio
>> +	 * domain in display power will be always turned on before operating
>> +	 * on the HDMI audio codec registers.
>> +	 */
>> +	device_link_add(component->card->dev, &hdev->dev,
>DL_FLAG_RPM_ACTIVE |
>> +			DL_FLAG_AUTOREMOVE_CONSUMER);
>
>Should device_link_free() be added to hdmi_codec_remove then?

As Takashi suggested, I add the DL_FLAG_AUTOREMOVE_CONSUMER flag.
This will make sure the link will be freed when machine driver are removed.
And as machine driver depends on the hdac_hdmi module, when
hdmi_codec_remove() is called, the link is freed already.

Regards,
Libin

>Thanks!