snd_hda_intel shutdown noise

snd_hda_intel shutdown noise

[Howard Chu]

On my HP dv5z whenever shutting down or rebooting there's a loud pop on the 
speakers just before the screen shuts off. It seems to me that it might be 
worthwhile to zero the volume or set the mute bit on the output channels just 
before closing the device. I started looking into this but haven't found the 
right place to insert the code yet. Anyone else have any ideas? Will this even 
make a difference?
-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/

Re: snd_hda_intel shutdown noise

[Takashi Iwai]

At Thu, 02 Oct 2008 21:59:59 -0700,
Howard Chu wrote:
> 
> On my HP dv5z whenever shutting down or rebooting there's a loud pop on the 
> speakers just before the screen shuts off. It seems to me that it might be 
> worthwhile to zero the volume or set the mute bit on the output channels just 
> before closing the device. I started looking into this but haven't found the 
> right place to insert the code yet. Anyone else have any ideas? Will this even 
> make a difference?

Not always, and pretty depending on the hardware design.

A simple test is just to mute volumes before shutdown/reboot.  If this
still causes the noise, then it's not about the volume mute switch.


Takashi