[alsa-devel] [Audio Driver Low power state]
gomathi.techgig at gmail.com
Wed Mar 26 05:20:40 CET 2014
I am new to kernel work and am trying to understand the low power state of
I am using ALC262 codec, hda_intel and 3.10 kernel code.
In this codec, d3_stop_clk flag is not set. So in the code flow I was able
to understand the following.
if (!codec->pm_down_notified &&
!bus->power_keep_link_on && (state & AC_PWRST_CLK_STOP_OK))
this particular condition in hda_power_work function fails, as
power_keep_link_on flag is directly based on d3_stop_clk flag.
codec->d3_stop_clk = snd_hda_codec_get_supported_ps(codec, fg,
I modified the if condition to not check the power_keep_link_on flag. After
this change the audio is consuming lesser power, but I am not able to see
it going to suspend/runtime suspend.
*Please clarify what is happening when I modify the if condition and how
audio device is consuming low power?*
*Also please help me understand, the significance of flags EPSS and
D3_STOP_CLK and if they can be set by software code. *
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