Re: [alsa-devel] HD-Audio: can msleep in hda_set_power_state() to D3 be optional?

At Thu, 28 Nov 2013 15:07:48 +0000, Lin, Mengdong wrote:

Hi Takashi,

In hda_set_power_state(), there is a mandatory sleep up to 100ms before setting state to D3.

/* this delay seems necessary to avoid click noise at power-down */ if (power_state == AC_PWRST_D3) { msleep(codec->epss ? 10 : 100); ... Could this be optional for specific codecs? flags = HDA_RW_NO_RESPONSE_FALLBACK; }

Some codecs implement their own sleep in patch_ops.suspend() to avoid the noise. So is it okay to add a codec flag to decide whether the sleep is necessary here?

Rather add an integer value to indicate the codec delay, e.g. codec->d3_delay. If it's zero, we can take the default delay (10 or 100) as of now.

Takashi