Hi Chris,
Would you run http://www.alsa-project.org/alsa-info.sh and email the results?
Thanks, Fengguang
On Thu, Mar 24, 2011 at 01:35:54AM +0000, Chris Wilson wrote:
---------- Forwarded message ---------- Date: Thu, 24 Mar 2011 00:49:55 +0000 (GMT) From: Chris Wilson chris@qwirx.com To: Takashi Iwai tiwai@suse.de, PeiSen Hou pshou@realtek.com.tw, matt.jared@intel.com, andy.kopp@intel.com, dan.d.kogan@intel.com Subject: Loud pops from Intel HDA onboard sound, may damage speakers
Dear sirs,
I'm writing to you as the named contacts in hda_intel.c in the Linux kernel. Please let me know if I should contact someone else instead.
I refer to this downstream bug on Ubuntu Launchpad, which I am hereby taking upstream: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/184632
I have a desktop system (Fujitsu P9900) with the onboard sound connected to my hi-fi amplifier, driven by snd_hda_intel. The audio chipset is:
00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 05)
The sound card outputs loud popping sounds whenever I suspend and resume it. One of them is loud or severe enough to cause my hi-fi amplifier to go into automatic shutdown mode, and I'm worried that it may damage my speakers.
If I enable power_save=1, as suggested by powertop, then this happens about 2 seconds after any audio finishes playing as well, so I suspect it's related to putting the sound card in or out of suspend mode.
The pops seem to be happening to others who have this chipset as well, as seen on the bug report, but they seem mostly to be using laptops or otherwise not bothered by potential damage to their speakers.
I would really appreciate it if you could help me to find a way to avoid these pops, for example by muting the audio output before shutting down the DAC? I think it would be great if this could make it into the standard kernel driver.
Many thanks in advance,
Chris Wilson.
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