Re: pulseaudio / alc1220 sound clicks interruptions etc

On Wed, Jun 4, 2025 at 9:56 PM Olivier Certner <olce@freebsd.org> wrote:
> The common denominator of all your reports seems to be Intel Hybrid Architecture (Alder Lake and onwards), which the scheduler does not especially support now.  I'm currently working on this support (this is not going to be ready soon).
>
> Could you please try the following (preferably 1):
> 1. Disable E (Efficiency) cores from your BIOS if possible, reboot, test again and report.
> 2. Pin the application reading audio to a P (Performance) core with cpuset, test again and report.  To know which cores are performance ones, run 'cpucontrol -i 0x1a /dev/cpuctlXXX' on your cores and check that the first hexadecimal value starts with 4 (a 2 indicates an efficiency core).
>
> If that doesn't show any difference, something else is at play and we'll then advise.

So I have disabled all E cores and this does not help - I even had all
USB port hang, and right after reboot there was kernel panic (probably
from nvidia driver need to setup serial port for logs sorry). I did
not test the E cores only enables though.

After that in BIOS I re-enabled all E cores and disabled all power
management, intel speed step (basic and advanced), now I cannot see
what frequency cores have, system seems to run at max speed all the
time, all is smooth.. but still there are micro-freezes in the audio.
I have launched ocp-curses with music playing from the console before
starting Xorg then in launched VLC so I had two streams to compare,
and did some applications launches - OSS from the background had minor
glitches (clicks) and freezes (brrrt) when launching bigger
applications, while VLC using PulseAudio had silent pauses (far longer
than oss glitches). But the system seems more stable right now.

Then, on the same power maxed setup I disabled nvidia module,
rebooted, configured Xorg to use SCFB, and all works smoothly!!! No
audio glitches, no clicks, no hiccups, both in terminal/oss/ocp and
xorg/pulseaudio/vlc !! I have only single screen output but
surprisingly I have ~160fps on the WM as opposed to ~20fps on the
nvidia driver (570.153.02 on FreeBSD-14.2 AMD64).

Why we suspect nvidia / drm to be the problem? Because we both with
Amar have nvidia gpu, for me on the old hardware the same card was
rock solid. I have tested various different WM: Enlightenment, XFCE4,
Awesome, KDE6, sometimes after some GL application close computer
froze and rebooted, sometimes between WM switch I was able to see
kernel panic message in the console right after Xorg shutdown. And
SCFB test seems to confirm the problem.. its nvidia or something it
uses below in the kernel.

By the way I had also whole machine stability problems with AMDGPU DRM
this is why I switched to NVIDIA. After CPU/MOBO/RAM replacement
problems seems back but with the nvidia this time. Maybe its some sort
of general DRM problem then if all works fine on bare metal SCFB where
no DRM is involved at all?

The problem is SCFB does not support multi screen setup with screen
rotation (one of my screens is vertical for better text reading). We
are clearly missing a solid fallback in this kind of situations :-(

Amar could you please try disabling the nvidia module and running Xorg
on SCFB framebuffer to see if that solves problem on your setup?

Hope that helps a bit :-)
Tomek


--
CeDeROM, SQ7MHZ, http://www.tomek.cedro.info