Bug 202185

Summary: Audio popping/clicking at boot but NOT after resume/suspend
Product: Drivers Reporter: Kadir (kadir)
Component: Sound(ALSA)Assignee: Jaroslav Kysela (perex)
Status: NEW ---    
Severity: normal    
Priority: P1    
Hardware: Intel   
OS: Linux   
Kernel Version: 4.19.13-300.fc29.x86_64 Subsystem:
Regression: No Bisected commit-id:
Attachments: alsa-info.sh output

Description Kadir 2019-01-08 18:57:02 UTC 
Created attachment 280343 [details]
alsa-info.sh output

Hi, 

I have a Dell Latitude 7480 and a stranger than usual audio popping/clicking/crackling issue. I run Fedora 29, fully updated.

The thing is when I boot the laptop, the audio clicks at certain low sound volumes or events. For example when testing the speakers in the Gnome sound settings panel causes multiple clicks/pops. Listening to a audio/video file with certain silent parts causes pops/clicks.

I have tried (almost) everything. Changing Pulseaudio setting does not work. Running a pure Jack system does not work. So the issue is not with Pulseaudio or Jack. I have tried disabling Intel HDA powersaving, that also does not work. 

But all problems disappear when I suspend and then resume the laptop. After resuming, everything works great. So at boot there are sound issues, but after a suspend/resume cycle everything is fine!

See https://bugzilla.redhat.com/show_bug.cgi?id=1525104#c108 for more information and testing. I also attached alsa-info.sh.
Comment 1 Kadir 2019-01-09 17:06:22 UTC 
I did some further digging around...found the following out:

Cold boot:

1. difference between alsa-info.sh at boot vs after a resume/suspend cycle

run 1

[latitude@latitude-7480 ~]$ diff alsa-info_cold_boot.txt alsa-info_resume1.txt 
6c6
< !!Script ran on: Wed Jan  9 16:12:28 UTC 2019
---
> !!Script ran on: Wed Jan  9 16:15:33 UTC 2019
68,75c68,75
< /sys/bus/acpi/devices/PNP0C0F:00/status 	 9
< /sys/bus/acpi/devices/PNP0C0F:01/status 	 9
< /sys/bus/acpi/devices/PNP0C0F:02/status 	 9
< /sys/bus/acpi/devices/PNP0C0F:03/status 	 9
< /sys/bus/acpi/devices/PNP0C0F:04/status 	 9
< /sys/bus/acpi/devices/PNP0C0F:05/status 	 9
< /sys/bus/acpi/devices/PNP0C0F:06/status 	 9
< /sys/bus/acpi/devices/PNP0C0F:07/status 	 9
---
> /sys/bus/acpi/devices/PNP0C0F:00/status        11
> /sys/bus/acpi/devices/PNP0C0F:01/status        11
> /sys/bus/acpi/devices/PNP0C0F:02/status        11
> /sys/bus/acpi/devices/PNP0C0F:03/status        11
> /sys/bus/acpi/devices/PNP0C0F:04/status        11
> /sys/bus/acpi/devices/PNP0C0F:05/status        11
> /sys/bus/acpi/devices/PNP0C0F:06/status        11
> /sys/bus/acpi/devices/PNP0C0F:07/status        11
546c546
< crw-rw----+ 1 root audio 116,  2 Jan  9 17:11 /dev/snd/pcmC0D0p
---
> crw-rw----+ 1 root audio 116,  2 Jan  9 17:14 /dev/snd/pcmC0D0p

run 2 (another resume/suspend cycle)
no difference except date/time

2. cat /proc/interrupts | grep snd

at boot 
 132:       2936          0          0          0  IR-PCI-MSI 514048-edge      snd_hda_intel:card0

after resume/suspend cycle
 130:          0          0          3          0  IR-PCI-MSI 514048-edge      snd_hda_intel:card0
 130:          0          0        999          0  IR-PCI-MSI 514048-edge      snd_hda_intel:card0

It seems to be switching IRQs with the ethernet card, I tried turning off the ethernet device (found another bug with the ethernet device in the process...) in the BIOS and this time snd_hda_intel did not switch IRQs after resume/suspend, but the clicking was still present at cold boot and disappeared at resume/suspend cycle

So nothing important I assume, but this is all I could find, I still have no clue as to why this is happening :)