Bug#867548: Playback to HDMI monitor stutters / pauses (HDMI on Haswell)

[Jmkr]

I can confirm that this bug still affects my Debian 10 systems that have kernel 
from Debian 12 (currently 6.1.0-20-amd64) and use Haswell CPU (e.g. Intel Core 
i74800MQ, i74810MQ, etc.). I have "VT-d" enabled in the BIOS of these laptops 
and I tested that this bug occurs when I connect external monitor via:

- HDMI port on the laptop to HDMI port on the monitor
- DP or DVI port on the laptop docking station to DP or HDMI port on the monitor

and then I ensure PULSEAUDIO outputs sound to the monitor DP or HDMI port. I 
also tested that passing "intel_iommu=on,igfx_off" to the kernel command line 
(in GRUB config or command line) still works as a workaround.

Also on my systems I noticed that if I set PULSEAUDIO to output sound to the 
monitor DP or HDMI and then start a YOUTUBE playback the audio/video starts for 
a brief moment normally and then it starts to stutter and then it quickly fails 
completely. Basically it looks like the playback speed starts as normal, but 
then quickly increases until it is too fast for the system to handle. To test 
this I switched PULSEAUDIO (using PAVUCONTROL) to "Analog Stereo Duplex" and 
then back to the monitor DP or HDMI ("Digital Stereo (HDMI*)") after each 
YOUTUBE playback attempt failed.

After reading this bug and the related kernel bug 
(https://bugzilla.kernel.org/show_bug.cgi?id=60769) I thing that Bryan Cebuliak 
and me experienced that kernel IOMMU bug that affects systems with Haswell 
CPUs. However the initial reporter Daniel Pocock and Mike Fuller could had a 
slightly different issue with HDMI audio. But it is hard to tell as they did 
not describe the symptoms in much detail. So we may never know unless they 
report back whether they still have problems with HDMI audio and whether the 
"intel_iommu=on,igfx_off" kernel parameter works as a workaround for them too.

Anyway, I would like to thank Bryan Cebuliak as the information he provided 
helped me find the workaround faster.

Regards,
Jmkr

Bug#867548: playback to HDMI monitor stutters / pauses

[Felipe Sateler]

On Jul 7, 2017 13:06, "Daniel Pocock"  wrote:



On 07/07/17 18:07, Felipe Sateler wrote:
> Control: tags -1 moreinfo
>
> On Fri, Jul 7, 2017 at 4:53 AM, Daniel Pocock  > wrote:
>
> Package: pulseaudio
> Version: 10.0-1
> Severity: important
>
> When playing audio through the HDMI monitor, I've noticed it
> stutters/pauses every few seconds, very briefly, less than a second
each
> time.  It is very irritating to listen to.
>
> In the middle of playback, I can open the GNOME settings panel for
sound
> and switch the output to another device (e.g. my USB sound card
> connected to an amp with an optical cable) and it works fine.  As soon
> as I switch back to the HDMI output the problem comes back.
>
>
> Could you attach a verbose log please?
>
> https://wiki.ubuntu.com/PulseAudio/Log
>


After following those instructions, I don't hear any playback at all



Strange. Any errors in the logfile?


I notice the killall command doesn't actually kill every pulseaudio
process, there is a process running as user Debian-gdm.  Do I need to do
something to stop that too before logging will work?



No, that is not necessary.

Bug#867548: playback to HDMI monitor stutters / pauses

[Daniel Pocock]

On 07/07/17 18:07, Felipe Sateler wrote:
> Control: tags -1 moreinfo
> 
> On Fri, Jul 7, 2017 at 4:53 AM, Daniel Pocock  > wrote:
> 
> Package: pulseaudio
> Version: 10.0-1
> Severity: important
> 
> When playing audio through the HDMI monitor, I've noticed it
> stutters/pauses every few seconds, very briefly, less than a second each
> time.  It is very irritating to listen to.
> 
> In the middle of playback, I can open the GNOME settings panel for sound
> and switch the output to another device (e.g. my USB sound card
> connected to an amp with an optical cable) and it works fine.  As soon
> as I switch back to the HDMI output the problem comes back.
> 
> 
> Could you attach a verbose log please?
> 
> https://wiki.ubuntu.com/PulseAudio/Log
>  


After following those instructions, I don't hear any playback at all

I notice the killall command doesn't actually kill every pulseaudio
process, there is a process running as user Debian-gdm.  Do I need to do
something to stop that too before logging will work?

Regards,

Daniel

Bug#867548: playback to HDMI monitor stutters / pauses

[Felipe Sateler]

Control: tags -1 moreinfo

On Fri, Jul 7, 2017 at 4:53 AM, Daniel Pocock  wrote:

> Package: pulseaudio
> Version: 10.0-1
> Severity: important
>
> When playing audio through the HDMI monitor, I've noticed it
> stutters/pauses every few seconds, very briefly, less than a second each
> time.  It is very irritating to listen to.
>
> In the middle of playback, I can open the GNOME settings panel for sound
> and switch the output to another device (e.g. my USB sound card
> connected to an amp with an optical cable) and it works fine.  As soon
> as I switch back to the HDMI output the problem comes back.
>

Could you attach a verbose log please?

https://wiki.ubuntu.com/PulseAudio/Log

-- 

Saludos,
Felipe Sateler

Bug#867548: playback to HDMI monitor stutters / pauses

[Daniel Pocock]

Package: pulseaudio
Version: 10.0-1
Severity: important

When playing audio through the HDMI monitor, I've noticed it
stutters/pauses every few seconds, very briefly, less than a second each
time.  It is very irritating to listen to.

In the middle of playback, I can open the GNOME settings panel for sound
and switch the output to another device (e.g. my USB sound card
connected to an amp with an optical cable) and it works fine.  As soon
as I switch back to the HDMI output the problem comes back.